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.