Justin Timberlake is accused of hooking up with Rihanna behind girlfriend Jessica Biel’s back.

The singer, who teamed up the “Umbrella” hitmaker on her third album, Good Girl Gone Bad may soon dump Jessica, The Herald Sun reported Wednesday.

“Justin and Rihanna have been seeing each other for the past few weeks,” whispers a spy. “He is really into her and it’s only a matter of time before he dumps Jessica.”

The pair are also alleged to be the subject of a recent New York Daily News blind item about a female star giving a male singer a “private” lapdance.

“That blind item about which two pop stars made sweet music together, the girl giving the guy a lapdance is Rihanna and JT!” the insider adds. “It was at 10ak in NYC and they left together. They are seeing each other on the low!”