Facebook already allows businesses to have conversations with Messenger's 1.2 billion monthly users and send them sponsored content.
Facebook Inc said that it was testing advertising on its Messenger app globally as the world's largest social media company looks to further monetise its popular chat service.
Ads will be displayed on the home tab of the Messenger app, Facebook said, adding that users clicking on the ads will either be taken to the advertiser's website or to a chat window.
