diff --git a/src/AnnotationThread.js b/src/AnnotationThread.js
index d07a9ac2c..885a0c8af 100644
--- a/src/AnnotationThread.js
+++ b/src/AnnotationThread.js
@@ -585,7 +585,8 @@ class AnnotationThread extends EventEmitter {
                 threadID: this.threadID
             },
             message,
-            createdBy: this.api.user
+            createdBy: this.api.user,
+            thread: this.threadNumber
         };
     }
 
diff --git a/src/__tests__/AnnotationThread-test.js b/src/__tests__/AnnotationThread-test.js
index e3e363ead..3422426a7 100644
--- a/src/__tests__/AnnotationThread-test.js
+++ b/src/__tests__/AnnotationThread-test.js
@@ -171,6 +171,28 @@ describe('AnnotationThread', () => {
         });
     });
 
+    describe('createAnnotationData()', () => {
+        it('should create an annotation data object to post to the API', () => {
+            const message = 'something';
+            const type = 'point';
+            const data = thread.createAnnotationData(type, message);
+            expect(data).toStrictEqual({
+                item: {
+                    type: 'file_version',
+                    id: '1'
+                },
+                details: {
+                    type,
+                    location: {},
+                    threadID: '2'
+                },
+                message,
+                createdBy: { id: '1' },
+                thread: '1'
+            });
+        });
+    });
+
     describe('updateTemporaryAnnotation()', () => {
         const tempAnnotation = { id: 1 };
         const serverAnnotation = {