Lady Gaga had a special surprise for the audience of her ENIGMA show on Saturday night as she brought her A Star is Born costar Bradley Cooper onstage to perform their Oscar-nominated smash "Shallow" for the first time live. "A really good friend of mine came to the show tonight. I don't know if you know him, but his name is Bradley," Gaga joked. "He made that movie, A Star Is Born. Yo Bradley, you wanna come do this one with me?"

"Shallow" is set to be performed at the 91st Academy Awards in February, where it's up for Best Original Song. The track, which Gaga co-wrote with Mark Ronson, Andrew Wyatt, and Anthony Rossomando, has won every award it's been nominated so far, including a Golden Globe, a Critics' Choice Award, a Hollywood Music in Media Award, and a Satellite Award.

Watch Gaga and Bradley sing "Shallow" live at ENIGMA below...