Justin Bieber cheated on Selena Gomez with Rihanna?

Los Angeles: Teen pop star Justin Bieber allegedly had an affair with Rihanna, according to a report.

The teen idol is said to have cheated on his on-off girlfriend Selena Gomez towards the beginning of their relationship with the `Umbrella` hitmaker Rihanna, reported Radar online. "It has devastated her," a friend of Gomez and Bieber said. The source alleges that 18-year-old Bieber got together with Rihanna after flirting with each other at a basketball game in Los Angeles back in February 2011. "It really cut like a knife because it happened in February of 2011, when Selena and Justin had been dating for months and were falling in love," the friend said. "It`s caused Selena to question their entire relationship. Selena thinks maybe they`ve been hooking up all along," the friend added. Bieber and Gomez started dating in late 2010, but have split up on more than one occasion in recent months. PTI