It will add selfie stickers, so Instagram users can reply in chats with personlised emoji-style icons. A watch together feature allows you and a friend to view Instagram video posts together on a video call.
And, you will be able to chat with your Instagram friends through Facebook Messenger and vice versa.
Some of the other features "borrowed" from Messenger include vanish mode, where chats disappear after they are seen or when you close a chat, and chat colours, where you can personalise your feed with coloured gradiants.
Custom emoji reactions will enable a shortcut of your favourite emojis, and you will be able to foward content with up to five friends and groups.
The update will also include the ability to reply to individual posts in a group directly, plus add messaging controls to let you select who can message you directly (or not). And finally, animated send effects will be available to spruce up chats.
There is no exact timescale on when you might received the update, but it seems that it will depend on your location: "We're rolling out these new features on Instagram and Messenger in a few countries around the world, and we’ll expand globally soon," said Facebook in a blog post.