Rihanna got in trouble for "repeatedly touching" lap dancers in a strip club.

The 'S&M' hitmaker allegedly angered security guards at Stringfellows in London during a visit with her ex-boyfriend Matt Kemp on Wednesday (12.10.11) because she couldn't keep her hands off the topless performers and even put her head between one of the dancers' legs.

A source told The Sun newspaper: "Rihanna couldn't resist paying for a dance and loved watching the girls in action. But the guards weren't happy as she was repeatedly touching them, ignoring all the warnings.

"At one point she thrust her head between the legs of one of the dancers."

The 23-year-old pop superstar and the baseball player partied until 2am in a private booth, where they were joined by celebrity hairdresser Adee Phelan and retired world heavyweight champion boxer David Haye.

Earlier in the night, Rihanna - who was named Esquire's Sexiest Woman Alive 2011 earlier this week - sang Guns N' Roses songs at the Nove Karaoke Bar in London's West End.

The sexy singer - who is in the UK on tour - went to the bar with several of her staff to celebrate a crew member's birthday and she treated the party to beers and vodka shots and food including pizza and garlic bread.

Rihanna couldn't stop grabbing the microphone and also performed renditions of her own tracks and Kings Of Leon's 'Sex on Fire'.