<p>Teen pop star Justin Bieber allegedly had an affair with Rihanna, according to a report.<br /><br /></p>.<p>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.<br /><br />"It has devastated her," a friend of Gomez and Bieber said.<br /><br />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.<br /><br />"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.<br /><br />"It's caused Selena to question their entire relationship. Selena thinks maybe they've been hooking up all along," the friend added.<br /><br />Bieber and Gomez started dating in late 2010, but have split up on more than one occasion in recent months.</p>
<p>Teen pop star Justin Bieber allegedly had an affair with Rihanna, according to a report.<br /><br /></p>.<p>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.<br /><br />"It has devastated her," a friend of Gomez and Bieber said.<br /><br />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.<br /><br />"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.<br /><br />"It's caused Selena to question their entire relationship. Selena thinks maybe they've been hooking up all along," the friend added.<br /><br />Bieber and Gomez started dating in late 2010, but have split up on more than one occasion in recent months.</p>