The couple split several years ago before rekindling their romance in July 2010. Despite their breakup, the "Judas" singer credits Carl, a musician and bartender, for helping her become "successful" in the music industry.
"I've really never loved anyone like I loved him. Or like I love him," she told Rolling Stone last year. "That relationship really shaped me. I sort of resolved that if you can't have the guy of your dreams, there are other ways to give love."
Hours after announcing her breakup to the world, Gaga performed a private concert, Belvedere Presents Born This Way, at Annabel's in London; she played five songs from her new album while celebrities including Kate Moss, Florence Welch, will.i.am and Geri Halliwell cheered her on.