Facebook is up against strong competition for video calling from Snapchat (Android | i OS), Google Hangouts (Android | i OS), Skype (Android | i OS), and other messaging apps.
The update is being pushed out to users in Belgium, Canada, Croatia, Denmark, France, Greece, Ireland, Laos, Lithuania, Mexico, Nigeria, Norway, Oman, Poland, Portugal, the UK, the US and Uruguay.
The video calling feature in Messenger is designed for speed.
Users can start a video chat from a message by tapping on the video icon at the top.
Last week, the company released a stand-alone web app for chatting on your computer.