WATCH: Bradley Cooper, Lady Gaga Sing 'Shallow' In Vegas

Lady Gaga and Bradley Cooper performed their hit “Shallow” live together for the first time Saturday during the pop star’s residency show Enigma in Las Vegas.

Cooper, who was sitting in the audience, was coaxed by Gaga to join her on stage.

“So a really good friend of mine… I don’t know if you know him but his name is Bradley. He made that movie, umm, A Star Is Born,” she said. “So I’m gonna be a little chance-y… Yo Bradley, you wanna come up and do this one?”

As fans went wild, Cooper made his way to the stage and the pair performed the duet their characters Jackson and Ally do in the film.

Cooper and Gaga will likely be called on to sing it again live at the Academy Awards, where it's nominated for Best Original Song.

"Shallow" has already won a Golden Globe and Critic's Choice Award and is also nominated for a Grammy.

Watch fan-shot video of the special moment here: