The film's director Barry Sonnenfeld confirmed their cameos in a recent interview, suggesting that they will appear on an alien surveillance board.
Sonnenfeld told Collider: "In this [film] there are a few people that you'll see up on the surveillance board including Lady GaGa, Tim Burton, who probably knows more about aliens than I do, and let's see who else... Justin Bieber."
In the two previous films, the alien surveillance board has featured cameos from Steven Spielberg, George Lucas and Sylvester Stallone.
"The challenge is getting celebrities that are famous, will give you permission and won't be like 'Who's that guy?' in ten years," Sonnenfeld continued.
The third instalment in the Men In Black series sees Smith's Agent J travelling back in time to save his partner Agent K, played as a younger man by Josh Brolin. The film also stars Tommy Lee Jones, Jemaine Clement, Emma Thompson, Alice Eve and Bill Hader.
Will Smith previously let slip that GaGa would make an appearance.
Former X Factor judge Nicole Scherzinger will play a villain in the film.
Men In Black III is released in the UK and US on May 25.
Watch the trailer below: