Rihanna and Kanye West have reportedly been caught in a liplock backstage at one of rapper T.I.'s LA concerts.

The Umbrella star is rumoured to have been sitting on Kanye's knee singing, before puckering up for the hip-hop star.

A source tells Star magazine, "Rihanna was sitting on Kanye's lap, singing along to the music.

“Before long, the two were full-on kissing each other. People were shocked.

“After a while, Rihanna must have realized people were watching, because she had her security escort her back to the dressing room."

Rihanna and her boyfriend Chris Brown were recently rumoured to be house hunting together.

Forget house hunting, we bet Chris will be scouting for a new girlfriend after he gets wind of the news.