Their sizzling performance of "Shallow" from "A Star Is Born" practically broke the internet, with the pair's locked gazes becoming an instant meme.
“Get a room,” read one tweet.
“Um, should we leave? Seems like they want to be alone,” went another.
“I'm sorry, but if you're Bradley’s [girlfriend], aren't you just...slightly...nervous?” wrote a third.
Cooper's girlfriend, supermodel Irina Shayk, was watching it all from the front row. She seemed unfazed, however, taking part in a standing ovation at the end of the performance.
A behind-the-scenes video later surfaced showing Cooper and Gaga returning to their seats during a commercial break. Cooper gave Shayk a sweet smooch, as Gaga stood nearby.
Gaga, who announced just last week that she and her fiancé had broken up, paid tribute to Cooper during her acceptance speech, when she won Best Original Song.
“Bradley, there is not a single person on the planet that could've sang this song with me but you. Thank you for believing in us. Thank you so much,” she said.
Gaga said Cooper choreographed their intimate performance, which began with the stars walking on stage without any introduction.