Twilight couple Kristen Stewart and Robert Pattinson have called off their romance, according to a U.S. report. The Hollywood stars have decided to go their separate ways after three years of dating, reports People magazine. The split news comes after Pattinson allegedly pulled out of celebrating his 27th birthday on 13 May (13) with Stewart, who is said to have planned a party for him. Just days before the British hunk's birthday, the pair appeared to be going strong as they partied together after the Costume Institute Gala in New York on 8 May (13) and they also flew back to Los Angeles at each other's side on 8 May (13). Their on/off relationship has been dogged by scandal - the actress stunned fans after admitting to an "indiscretion" with director Rupert Sanders last July (12). The ordeal ended Sanders' relationship with wife Liberty Ross and led Stewart to issue a public apology to Pattinson.