The A Star Is Born stars performed a stunning rendition of the Best Original Song-nominated track, "Shallow," during the 91st Academy Awards on Sunday. It was their first time performing it together live on air -- and Cooper performed it as himself, not as his character, Jackson Maine.
There was no intro needed for the two, who stood from their seats and took the stage right after a gorgeous Steinway & Sons piano was placed onstage. Cooper kicked off the performance, giving everyone goosebumps with his verses. Maintaining eye contact throughout, Gaga was seated at the piano to perform.
As Gaga belted out her verses, Cooper then stood from his stand and took a seat next to his co-star and completed the rest of their song singing together on the same mic. The chemistry was undeniable as their faces were closer than ever before and Gaga briefly put her head on his shoulders.
Cooper told ET's Kevin Frazier and Nancy O'Dell on the Oscars red carpet that not only did he sing the movie's songs to his little girl, she was very close to the editing process.
"First of all, we edited the movie below her room so she was inundated with noise for the first six months of her life," he quipped. "She [may] never want to hear that soundtrack for the rest of her life. Enough!"
That being said, Cooper has a musical home and sings lullabies to his little girl. "We sing a lot," he shared. "She loves to sing."
A Star Is Born was nominated for eight Oscars in total this year, including Best Picture, Best Actor and Best Adapted Screenplay for Cooper, Best Actress for Gaga and Best Supporting Actor for Sam Elliott.
Written by Gaga,Mark Ronson, Anthony Rossomando and Andrew Wyatt, "Shallow" already won a handful of awards this season, including a Golden Globe and a GRAMMY. Though Cooper and Gaga surprised fans by performing the duet during her Las Vegas show, Enigma, he told ET that he "couldn't sing before this movie."
"In terms of being able to sing in front of people, it's very nerve-racking," he admitted. "It's not easy, what they do."