"Why Did You Do That?" is a song recorded by American singer Lady Gaga for the 2018 film A Star Is Born and released on the soundtrack of the same name. It was written by Gaga with Diane Warren, Mark Nilan Jr., Nick Monson and Paul "DJWS" Blair, and produced by all but Warren. The song appears in the film during a sequence when Gaga's character, Ally, performs on Saturday Night Live, watched by her husband Jackson (played by co-star Bradley Cooper). Later Jackson berates Ally for selling out with the song's trite lyrics, but she defends it. "Why Did You Do That?" was written to evoke both a retro and a modern feel, and was recorded while Gaga was on her Joanne World Tour.