Bieber cheated on Gomez with RiRi?

New York: Just weeks after Justin Bieber and Selena Gomez broke up after their two-year relationship, a new report claims that they split after she found out that he was cheating with Rihanna.

Rihanna and Bieber have never seemed anything more than platonic, but Life and Style has claimed that the teen popstar's alleged dalliance is the "real" reason behind his breakup with Gomez, the New York Post reported.

According to the magazine, Gomez was "devastated" after she heard the shocking news that the 'Baby' hitmaker had cheated on her.

A friend of the former couple said that it was devastating for her.

"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.

The "insider" also said that Bieber "would never tell anyone he messed around with Rihanna because it would make him look like a dirty dog."

Another "insider" said that Bieber and Rihanna continued their "affair" while filming the Victoria's Secret Fashion Show last November.

A source close to the Barbadian singer laughed off the story and told GossipCop it was false, while a rep for Bieber also dismissed the report.