The song won Best Original Song, earning Gaga her first Academy Award alongside co-writer Mark Ronson.
Near the end of the performance at the Dolby Theatre in Los Angeles, Cooper joined Gaga at the piano, their heads resting together as they sang the last few notes.
While some have admired Gaga and Cooper’s close relationship, others have said how close they appeared during the duet.
“Isn’t Bradley Cooper in a relationship? Kind of weird how close and intimate he was getting with Lady Gaga,” one person wrote on Twitter.
“I’m still sitting here thinking about how close Lady Gaga and Bradley Cooper’s faces were at that piano,” another added.
Many people have defended the performance.
“I honestly don’t think @ladygaga and Bradley Cooper are secretly together. I just think if you are in her circle she loves you with that much intensity,” one person tweeted.
“It was an act on the stage, like they did on the film. Very dangerous to assume they are anything other than good friends,” another wrote.
For a full list of all the winners at the 2019 Academy Awards, click here.
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