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During Gaga's Enigma residency concert in Las Vegas, the singer invited her A Star Is Born co-star and director up on the stage with her. Cooper, who was seated in the audience, had the crowd cheering as he joined Gaga to perform their duet.
After sharing a hug, Gaga announced to Cooper, "I even got you in-ears."
"Jackson never used these," Cooper, referencing his character Jackson Maine, told the crowd as he prepared to perform.
Video footage from the concert shows Gaga helping Cooper get ready to sing, giving him a kiss on the cheek before he sat down.