Justin Bieber Twitter: Justin Bieber Cheating On Selena Gomez With A Mystery Blonde Girl? Bieber Says He’s ‘Having Fun’ [VIDEO]

Justin Bieber's Twitter update on Sunday said that he was "having fun" without Selena Gomez, who has released a new single, "Come and Get It." While driving around Los Angeles, Bieber was spotted with a mystery blonde girl, and rumors of Justin Bieber cheating on Selena Gomez have surfaced.

Justin Bieber's Twitter has been filled with all happy updates, as the 19-year-old singer said, "sundayfunday" yesterday and expressed his love for beach weather, saying, "beach weather all day. good stuff."

Justin Bieber and Selena Gomez have been having an on and off relationship for some time now and have recently reunited as a couple. While Selena Gomez was spotted shopping on her own, Justin Bieber was seen with a mystery blonde girl in the passenger seat of his car, according to MailOnline.

Justin Bieber was reportedly driving an SUV around Calabasas, Los Angeles on Sunday, and photos taken of him on that day showed a mystery blonde girl who was talking and joking around with Justin Bieber.

Is Justin Bieber cheating on Selena Gomez or is he and the mystery blonde girl just friends? Justin Bieber's Twitter says that the singer is "having fun" and "enjoying the much needed time off. just needed to come on here and say i appreciate all of u. thanks. love u."

All of these tweets were written and posted on Sunday, leading fans to speculate that Justin Bieber's good mood was derived from a happy day spent not with Selena Gomez but with the mystery blonde girl in his car.

However, some fans have come to Justin Bieber's defense by leaving comments on the MailOnline page, saying that the boy in the photo is not Justin Bieber, and that Justin Bieber should have been travelling in Miami rather than in Los Angeles.