diff --git a/ghost/collections/src/CollectionsRepositoryInMemory.ts b/ghost/collections/src/CollectionsRepositoryInMemory.ts
index 4c17a872b1..31e4eb8b08 100644
--- a/ghost/collections/src/CollectionsRepositoryInMemory.ts
+++ b/ghost/collections/src/CollectionsRepositoryInMemory.ts
@@ -3,12 +3,6 @@ import {Collection} from './Collection';
 
 export class CollectionsRepositoryInMemory extends InMemoryRepository<string, Collection> {
     protected toPrimitive(entity: Collection): object {
-        return {
-            title: entity.title,
-            slug: entity.slug,
-            description: entity.description,
-            feature_image: entity.featureImage,
-            type: entity.type
-        };
+        return entity.toJSON();
     }
 }
diff --git a/ghost/collections/src/CollectionsService.ts b/ghost/collections/src/CollectionsService.ts
index 13944133ea..2d7c8b3fde 100644
--- a/ghost/collections/src/CollectionsService.ts
+++ b/ghost/collections/src/CollectionsService.ts
@@ -12,7 +12,7 @@ const messages = {
 
 type CollectionsServiceDeps = {
     collectionsRepository: CollectionRepository;
-    postsRepository: IPostsRepository;
+    postsRepository: PostsRepository;
 };
 
 type CollectionPostDTO = {
@@ -61,23 +61,23 @@ type CollectionPostInputDTO = {
     published_at: Date;
 };
 
-type IPostsRepository = {
+interface PostsRepository {
     getAll(options: {filter?: string}): Promise<any[]>;
 }
 
 export class CollectionsService {
-    collectionsRepository: CollectionRepository;
-    postsRepository: IPostsRepository;
+    private collectionsRepository: CollectionRepository;
+    private postsRepository: PostsRepository;
 
     constructor(deps: CollectionsServiceDeps) {
         this.collectionsRepository = deps.collectionsRepository;
         this.postsRepository = deps.postsRepository;
     }
 
-    toDTO(collection: Collection): CollectionDTO {
+    private toDTO(collection: Collection): CollectionDTO {
         return {
             id: collection.id,
-            title: collection.title || null,
+            title: collection.title,
             slug: collection.slug,
             description: collection.description || null,
             feature_image: collection.featureImage || null,
@@ -92,7 +92,7 @@ export class CollectionsService {
         };
     }
 
-    fromDTO(data: any): any {
+    private fromDTO(data: any): any {
         const mappedDTO: {[index: string]:any} = {
             title: data.title,
             slug: data.slug,
@@ -151,7 +151,7 @@ export class CollectionsService {
         return this.toDTO(collection);
     }
 
-    async #updateAutomaticCollectionItems(collection: Collection, filter?:string) {
+    private async updateAutomaticCollectionItems(collection: Collection, filter?:string) {
         const collectionFilter = filter || collection.filter;
 
         if (collectionFilter) {
@@ -173,7 +173,7 @@ export class CollectionsService {
         });
 
         for (const collection of collections) {
-            await this.#updateAutomaticCollectionItems(collection);
+            await this.updateAutomaticCollectionItems(collection);
             await this.collectionsRepository.save(collection);
         }
     }
@@ -192,7 +192,7 @@ export class CollectionsService {
         }
 
         if ((collection.type === 'automatic' || data.type === 'automatic') && data.filter) {
-            await this.#updateAutomaticCollectionItems(collection, data.filter);
+            await this.updateAutomaticCollectionItems(collection, data.filter);
         }
 
         const collectionData = this.fromDTO(data);
@@ -226,6 +226,14 @@ export class CollectionsService {
         };
     }
 
+    async getCollectionsForPost(postId: string): Promise<CollectionDTO[]> {
+        const collections = await this.collectionsRepository.getAll({
+            filter: `posts:${postId}`
+        });
+
+        return collections.map(collection => this.toDTO(collection));
+    }
+
     async destroy(id: string): Promise<Collection | null> {
         const collection = await this.getById(id);
 
diff --git a/ghost/collections/test/collections.test.ts b/ghost/collections/test/collections.test.ts
index 03377ce2e1..c5565ac99d 100644
--- a/ghost/collections/test/collections.test.ts
+++ b/ghost/collections/test/collections.test.ts
@@ -1,5 +1,5 @@
 import assert from 'assert';
-import {CollectionsService, CollectionsRepositoryInMemory, Collection} from '../src/index';
+import {CollectionsService, CollectionsRepositoryInMemory} from '../src/index';
 import {PostsRepositoryInMemory} from './fixtures/PostsRepositoryInMemory';
 import {posts} from './fixtures/posts';
 
@@ -80,13 +80,19 @@ describe('CollectionsService', function () {
         });
     });
 
-    describe('toDTO', function () {
-        it('Can map Collection entity to DTO object', async function () {
-            const collection = await Collection.create({});
-            const dto = collectionsService.toDTO(collection);
+    describe('getCollectionsForPost', function () {
+        it('Can get collections for a post', async function () {
+            const collection = await collectionsService.createCollection({
+                title: 'testing collections',
+                type: 'manual'
+            });
 
-            assert.equal(dto.id, collection.id, 'DTO should have the same id as the entity');
-            assert.equal(dto.title, null, 'DTO should return null if nullable property of the entity is unassigned');
+            await collectionsService.addPostToCollection(collection.id, posts[0]);
+
+            const collections = await collectionsService.getCollectionsForPost(posts[0].id);
+
+            assert.equal(collections.length, 1, 'There should be one collection');
+            assert.equal(collections[0].id, collection.id, 'Collection should be the correct one');
         });
     });
 
diff --git a/ghost/core/core/server/api/endpoints/collections.js b/ghost/core/core/server/api/endpoints/collections.js
index 9c57dc1078..32ec8ffdb2 100644
--- a/ghost/core/core/server/api/endpoints/collections.js
+++ b/ghost/core/core/server/api/endpoints/collections.js
@@ -19,7 +19,7 @@ module.exports = {
         // @NOTE: should have permissions when moving out of Alpha
         permissions: false,
         query(frame) {
-            return collectionsService.api.browse(frame.options);
+            return collectionsService.api.getAll(frame.options);
         }
     },
 
@@ -30,7 +30,7 @@ module.exports = {
         // @NOTE: should have permissions when moving out of Alpha
         permissions: false,
         async query(frame) {
-            const model = await collectionsService.api.read(frame.data.id, frame.options);
+            const model = await collectionsService.api.getById(frame.data.id);
 
             if (!model) {
                 throw new errors.NotFoundError({
@@ -50,7 +50,7 @@ module.exports = {
         // @NOTE: should have permissions when moving out of Alpha
         permissions: false,
         async query(frame) {
-            return await collectionsService.api.add(frame.data.collections[0], frame.options);
+            return await collectionsService.api.createCollection(frame.data.collections[0]);
         }
     },
 
@@ -71,7 +71,7 @@ module.exports = {
         async query(frame) {
             const model = await collectionsService.api.edit(Object.assign(frame.data.collections[0], {
                 id: frame.options.id
-            }), frame.options);
+            }));
 
             if (!model) {
                 throw new errors.NotFoundError({
@@ -117,7 +117,7 @@ module.exports = {
         // @NOTE: should have permissions when moving out of Alpha
         permissions: false,
         async query(frame) {
-            const collectionPost = await collectionsService.api.addPost(frame.options.id, {
+            const collectionPost = await collectionsService.api.addPostToCollection(frame.options.id, {
                 id: frame.data.posts[0].id
             });
 
@@ -176,7 +176,7 @@ module.exports = {
         // @NOTE: should have permissions when moving out of Alpha
         permissions: false,
         async query(frame) {
-            const collection = await collectionsService.api.destroyCollectionPost(frame.options.id, frame.options.post_id);
+            const collection = await collectionsService.api.removePostFromCollection(frame.options.id, frame.options.post_id);
 
             if (!collection) {
                 throw new errors.NotFoundError({
diff --git a/ghost/core/core/server/api/endpoints/posts.js b/ghost/core/core/server/api/endpoints/posts.js
index 8fbaa2e700..69406301cf 100644
--- a/ghost/core/core/server/api/endpoints/posts.js
+++ b/ghost/core/core/server/api/endpoints/posts.js
@@ -1,6 +1,4 @@
 const models = require('../../models');
-const tpl = require('@tryghost/tpl');
-const errors = require('@tryghost/errors');
 const getPostServiceInstance = require('../../services/posts/posts-service');
 const allowedIncludes = [
     'tags',
@@ -21,10 +19,6 @@ const allowedIncludes = [
 ];
 const unsafeAttrs = ['status', 'authors', 'visibility'];
 
-const messages = {
-    postNotFound: 'Post not found.'
-};
-
 const postsService = getPostServiceInstance();
 
 module.exports = {
@@ -118,16 +112,7 @@ module.exports = {
             unsafeAttrs: unsafeAttrs
         },
         query(frame) {
-            return models.Post.findOne(frame.data, frame.options)
-                .then((model) => {
-                    if (!model) {
-                        throw new errors.NotFoundError({
-                            message: tpl(messages.postNotFound)
-                        });
-                    }
-
-                    return model;
-                });
+            return postsService.readPost(frame);
         }
     },
 
diff --git a/ghost/core/core/server/api/endpoints/utils/serializers/output/mappers/posts.js b/ghost/core/core/server/api/endpoints/utils/serializers/output/mappers/posts.js
index 5dda3654c0..ea53960ef5 100644
--- a/ghost/core/core/server/api/endpoints/utils/serializers/output/mappers/posts.js
+++ b/ghost/core/core/server/api/endpoints/utils/serializers/output/mappers/posts.js
@@ -24,7 +24,19 @@ const labs = require('../../../../../../../shared/labs');
 module.exports = async (model, frame, options = {}) => {
     const {tiers: tiersData} = options || {};
 
-    const jsonModel = model.toJSON(frame.options);
+    // NOTE: `model` is now overloaded and may be a bookshelf model or a POJO
+    let jsonModel = model;
+    if (typeof model.toJSON === 'function') {
+        jsonModel = model.toJSON(frame.options);
+    } else {
+        // This is to satisy the interface which extraAttrs needs
+        model = {
+            id: jsonModel.id,
+            get(attr) {
+                return jsonModel[attr];
+            }
+        };
+    }
 
     // Map email_recipient_filter to email_segment
     jsonModel.email_segment = jsonModel.email_recipient_filter;
diff --git a/ghost/core/core/server/services/collections/index.js b/ghost/core/core/server/services/collections/index.js
index ee72847a03..32b1b4bee2 100644
--- a/ghost/core/core/server/services/collections/index.js
+++ b/ghost/core/core/server/services/collections/index.js
@@ -4,6 +4,7 @@ const {
 } = require('@tryghost/collections');
 
 class CollectionsServiceWrapper {
+    /** @type {CollectionsService} */
     api;
 
     constructor() {
@@ -34,23 +35,15 @@ class CollectionsServiceWrapper {
             });
         }
 
-        this.api = {
-            browse: collectionsService.getAll.bind(collectionsService),
-            read: collectionsService.getById.bind(collectionsService),
-            add: collectionsService.createCollection.bind(collectionsService),
-            edit: collectionsService.edit.bind(collectionsService),
-            addPost: collectionsService.addPostToCollection.bind(collectionsService),
-            destroy: collectionsService.destroy.bind(collectionsService),
-            destroyCollectionPost: collectionsService.removePostFromCollection.bind(collectionsService)
-        };
+        this.api = collectionsService;
     }
 
     async init() {
-        const featuredCollections = await this.api.browse({filter: 'slug:featured'});
+        const featuredCollections = await this.api.getAll({filter: 'slug:featured'});
 
         if (!featuredCollections.data.length) {
             require('./built-in-collections').forEach((collection) => {
-                this.api.add(collection);
+                this.api.createCollection(collection);
             });
         }
     }
diff --git a/ghost/core/core/server/services/posts/posts-service.js b/ghost/core/core/server/services/posts/posts-service.js
index 0dc40e4a3f..0824941ff9 100644
--- a/ghost/core/core/server/services/posts/posts-service.js
+++ b/ghost/core/core/server/services/posts/posts-service.js
@@ -12,6 +12,7 @@ const getPostServiceInstance = () => {
     const emailService = require('../email-service');
     const settingsCache = require('../../../shared/settings-cache');
     const settingsHelpers = require('../settings-helpers');
+    const collectionsService = require('../collections');
 
     const postStats = new PostStats();
 
@@ -37,7 +38,8 @@ const getPostServiceInstance = () => {
         isSet: flag => labs.isSet(flag), // don't use bind, that breaks test subbing of labs
         stats: postStats,
         emailService: emailService.service,
-        postsExporter
+        postsExporter,
+        collectionsService: collectionsService.api
     });
 };
 
diff --git a/ghost/core/test/unit/server/services/collections/CollectionsServiceWrapper.test.js b/ghost/core/test/unit/server/services/collections/CollectionsServiceWrapper.test.js
index a279394fc0..582fef94af 100644
--- a/ghost/core/test/unit/server/services/collections/CollectionsServiceWrapper.test.js
+++ b/ghost/core/test/unit/server/services/collections/CollectionsServiceWrapper.test.js
@@ -1,18 +1,11 @@
 const assert = require('assert');
 const collectionsServiceWrapper = require('../../../../../core/server/services/collections');
+const {CollectionsService} = require('@tryghost/collections');
 
 describe('CollectionsServiceWrapper', function () {
     it('Exposes a valid instance of CollectionsServiceWrapper', async function () {
         assert.ok(collectionsServiceWrapper);
         assert.ok(collectionsServiceWrapper.api);
-        assert.deepEqual(Object.keys(collectionsServiceWrapper.api), [
-            'browse',
-            'read',
-            'add',
-            'edit',
-            'addPost',
-            'destroy',
-            'destroyCollectionPost'
-        ]);
+        assert.ok(collectionsServiceWrapper.api instanceof CollectionsService);
     });
 });
diff --git a/ghost/posts-service/lib/PostsService.js b/ghost/posts-service/lib/PostsService.js
index ea968f3160..e201fda9be 100644
--- a/ghost/posts-service/lib/PostsService.js
+++ b/ghost/posts-service/lib/PostsService.js
@@ -11,17 +11,37 @@ const messages = {
     invalidTiers: 'Invalid tiers value.',
     invalidTags: 'Invalid tags value.',
     invalidEmailSegment: 'The email segment parameter doesn\'t contain a valid filter',
-    unsupportedBulkAction: 'Unsupported bulk action'
+    unsupportedBulkAction: 'Unsupported bulk action',
+    postNotFound: 'Post not found.'
 };
 
 class PostsService {
-    constructor({urlUtils, models, isSet, stats, emailService, postsExporter}) {
+    constructor({urlUtils, models, isSet, stats, emailService, postsExporter, collectionsService}) {
         this.urlUtils = urlUtils;
         this.models = models;
         this.isSet = isSet;
         this.stats = stats;
         this.emailService = emailService;
         this.postsExporter = postsExporter;
+        this.collectionsService = collectionsService;
+    }
+
+    async readPost(frame) {
+        const model = await this.models.Post.findOne(frame.data, frame.options);
+
+        if (!model) {
+            throw new errors.NotFoundError({
+                message: tpl(messages.postNotFound)
+            });
+        }
+
+        const dto = model.toJSON(frame.options);
+
+        if (this.isSet('collections') && frame?.original?.query?.include?.includes('collections')) {
+            dto.collections = await this.collectionsService.getCollectionsForPost(model.id);
+        }
+
+        return dto;
     }
 
     async editPost(frame) {