The costars performed their original song from the Oscar-nominated A Star Is Born for the first time together during Lady Gaga's concert

Lady Gaga shocked fans during her Las Vegas concert when she pulled her A Star Is Born costar Bradley Cooper on stage for a surprise performance of their Golden Globe-winning original song from the film, “Shallow.”

In the middle of her Enigma residency show at the Park MGM on Saturday, the pop icon addressed the crowd: “So a really good friend of mine… I don’t know if you know him but his name is Bradley. He made that movie A Star Is Born.”

A fan-made video shows Cooper, who also directed Gaga in the film, sitting in a private area near the front of the audience. “So I’m gonna be a little chance-y,” she continued. “Yo Bradley, you wanna come up and do this one?”

Cooper agreed and made his way to the stage, where they shared a hug and she led him to the piano.

“I even got you in-ears,” Gaga, 32, said of the earbuds singers use to hear themselves in concert venues.

Bradley Cooper and Lady Gaga at her Las Vegas residency
| Credit: Denise Truscello/Getty Images for Park MGM
Bradley Cooper and Lady Gaga
| Credit: Denise Truscello/Getty Images for Park MGM

“Jackson never used these,” Cooper, 44, joked in reply, referencing his rebel character in the film.

Though he added, “I can’t hear anything,” Cooper seemed unfazed as he launched into a rendition of the song, which is nominated for an Oscar.

Gaga kneeled on the ground beside Cooper, who sat on a stool for the song and looked down at her warmly, resting a hand on her arm as he sang.

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Gaga then played the piano for the second verse before the two came together again for the chorus.

Cooper rocked out behind her, playing an air guitar as Gaga sang the emotional ballad. He then joined her on the piano bench and wrapped an arm around her to finish out the final chorus together.

Bradley Cooper and Lady Gaga

Gaga received a Best Actress Oscar nod for her role as Ally in the film, and though Cooper is nominated for Best Actor, he was snubbed for Best Director.

“At the end of the day, he knows that he’s the best director in my eyes, and in all of our eyes as his cast,” Gaga told the Los Angeles Times earlier this month. “I know that he’s so happy that we’ve all been nominated and that the film was recognized and we all feel really, really beyond elated for the recognition.”

The movie also garnered nominations for Best Picture, Best Supporting Actor (Sam Elliott), Best Adapted Screenplay, Best Cinematography and Best Sound Mixing.

The costars had never performed the song live together since production of A Star Is Born, but as Rolling Stone notes, they may be invited to do so at February’s Academy Awards. Variety reported on Thursday that only two songs will likely be part of the telecast: Kendrick Lamar and SZA’s “All the Stars” from Black Panther and “Shallow.”