To film the "Shallow" sequence, Cooper filled the Greek Theater with around 2,000 Gaga fans and then recorded the song. Following the filming, Gaga entertained the crowd playing piano versions of her old songs; Lukas Nelson and Promise of the Real also sang at the venue.

And throughout the film, you hear a raspier, deeper version of Cooper's voice as he joins Gaga's character Ally at the piano to write and later perform “Shallow.” It turns out that indeed, Cooper really is singing in the movie and on the soundtrack.

Tragically, the film ends with Jackson choosing to commit suicide. While he never used suicide as a threat against Ally, we do know that many abusive partners do use threats of suicide to manipulate their partner.

“I knew I wanted to lower my speaking voice an octave. So I hired [dialect coach] Tim Monich early on — I mean, like, a year before we shot the movie. He moved to L.A. and we worked five days a week, four hours a day on exercises and lowering my voice.”