diff --git a/src/thread.ts b/src/thread.ts
index 2278f43a1..788651357 100644
--- a/src/thread.ts
+++ b/src/thread.ts
@@ -41,11 +41,13 @@ export class Thread<StreamChatGenerics extends ExtendableGenerics = DefaultGener
     this.channel = t.channel;
     this._channel = client.channel(t.channel.type, t.channel.id);
     this._client = client;
-    for (const r of t.read) {
-      this.read[r.user.id] = {
-        ...r,
-        last_read: new Date(r.last_read),
-      };
+    if (t.read) {
+      for (const r of t.read) {
+        this.read[r.user.id] = {
+          ...r,
+          last_read: new Date(r.last_read),
+        };
+      }
     }
   }
 
@@ -53,8 +55,17 @@ export class Thread<StreamChatGenerics extends ExtendableGenerics = DefaultGener
     return this._client;
   }
 
+  /**
+   * addReply - Adds or updates a latestReplies to the thread
+   *
+   * @param {MessageResponse<StreamChatGenerics>} message reply message to be added.
+   */
   addReply(message: MessageResponse<StreamChatGenerics>) {
-    this.latestReplies = addToMessageList(this.latestReplies, formatMessage(message));
+    if (message.parent_id !== this.message.id) {
+      throw new Error('Message does not belong to this thread');
+    }
+
+    this.latestReplies = addToMessageList(this.latestReplies, formatMessage(message), true);
   }
 
   updateReply(message: MessageResponse<StreamChatGenerics>) {
@@ -77,6 +88,7 @@ export class Thread<StreamChatGenerics extends ExtendableGenerics = DefaultGener
 
     if (message.parent_id && message.parent_id === this.message.id) {
       this.updateReply(message);
+      return;
     }
 
     if (!message.parent_id && message.id === this.message.id) {
diff --git a/src/types.ts b/src/types.ts
index fd528479f..a7fa22642 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -673,6 +673,7 @@ export type OwnUserBase<StreamChatGenerics extends ExtendableGenerics = DefaultG
   total_unread_count: number;
   unread_channels: number;
   unread_count: number;
+  unread_threads: number;
   invisible?: boolean;
   roles?: string[];
 };
diff --git a/src/utils.ts b/src/utils.ts
index b3e9f8f26..9d20e49e6 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -84,6 +84,7 @@ export function isOwnUserBaseProperty(property: string) {
     total_unread_count: true,
     unread_channels: true,
     unread_count: true,
+    unread_threads: true,
     invisible: true,
     roles: true,
   };
diff --git a/test/unit/test-utils/generateMessage.js b/test/unit/test-utils/generateMessage.js
index 88436775b..4aa5dba93 100644
--- a/test/unit/test-utils/generateMessage.js
+++ b/test/unit/test-utils/generateMessage.js
@@ -4,7 +4,7 @@ export const generateMsg = (msg = {}) => {
 	const date = msg.date || new Date().toISOString();
 	return {
 		id: uuidv4(),
-		text: 'x',
+		text: uuidv4(),
 		html: '<p>x</p>\n',
 		type: 'regular',
 		user: { id: 'id' },
diff --git a/test/unit/test-utils/generateThread.js b/test/unit/test-utils/generateThread.js
new file mode 100644
index 000000000..93d322ec3
--- /dev/null
+++ b/test/unit/test-utils/generateThread.js
@@ -0,0 +1,21 @@
+import { v4 as uuidv4 } from 'uuid';
+import { generateUser } from './generateUser';
+
+export const generateThread = (channel, parent, opts = {}) => {
+	return {
+		parent_message_id: parent.id,
+		parent_message: parent,
+		channel,
+		title: 'title',
+		created_at: new Date().toISOString(),
+		updated_at: new Date().toISOString(),
+		channel_cid: channel.cid,
+		last_message_at: new Date().toISOString(),
+		deleted_at: '',
+		read: [],
+		reply_count: 0,
+		latest_replies: [],
+		thread_participants: [],
+		...opts,
+	};
+};
diff --git a/test/unit/thread.js b/test/unit/thread.js
new file mode 100644
index 000000000..d0501c421
--- /dev/null
+++ b/test/unit/thread.js
@@ -0,0 +1,70 @@
+import chai from 'chai';
+import { v4 as uuidv4 } from 'uuid';
+
+import { generateChannel } from './test-utils/generateChannel';
+import { generateMember } from './test-utils/generateMember';
+import { generateMsg } from './test-utils/generateMessage';
+import { generateUser } from './test-utils/generateUser';
+import { getClientWithUser } from './test-utils/getClient';
+import { getOrCreateChannelApi } from './test-utils/getOrCreateChannelApi';
+import sinon from 'sinon';
+import { mockChannelQueryResponse } from './test-utils/mockChannelQueryResponse';
+
+import { ChannelState, StreamChat, Thread } from '../../src';
+import { generateThread } from './test-utils/generateThread';
+
+const expect = chai.expect;
+
+describe.only('Thread', () => {
+	describe('addReply', async () => {
+		let client;
+		let channel;
+		let parent;
+		let thread;
+
+		beforeEach(() => {
+			client = new StreamChat('apiKey');
+			client.userID = 'observer';
+			channel = generateChannel().channel;
+			parent = generateMsg();
+			thread = new Thread(client, generateThread(channel, parent));
+		});
+		it('should throw error if the message is not a reply to the parent', async () => {
+			const reply = generateMsg({
+				status: 'pending',
+				parent_id: 'some_other_id',
+			});
+			expect(() => thread.addReply(reply)).to.throw('Message does not belong to this thread');
+		});
+
+		it('should add reply to the thread', async () => {
+			const reply1 = generateMsg({
+				status: 'pending',
+				parent_id: parent.id,
+			});
+
+			thread.addReply(reply1);
+			expect(thread.latestReplies).to.have.length(1);
+			expect(thread.latestReplies[0].status).to.equal('pending');
+
+			reply1.status = 'received';
+			thread.addReply(reply1);
+			expect(thread.latestReplies).to.have.length(1);
+			expect(thread.latestReplies[0].status).to.equal('received');
+
+			const reply2 = generateMsg({
+				status: 'pending',
+				parent_id: parent.id,
+			});
+
+			thread.addReply(reply2);
+			expect(thread.latestReplies).to.have.length(2);
+			expect(thread.latestReplies[1].status).to.equal('pending');
+
+			reply2.status = 'received';
+			thread.addReply(reply2);
+			expect(thread.latestReplies).to.have.length(2);
+			expect(thread.latestReplies[1].status).to.equal('received');
+		});
+	});
+});