Los Angeles: Pop diva Britney Spears' surprise appearance caused chaos at R&B star Nicki Minaj's party as security guards struggled to control the over-excited crowd.

Minaj, 26, took to the stage for an after party on Friday night following her performance with Lil Wayne at the city's Staples Center.

Minaj’s soon-to-be-touring partner Spears showed up at the event and joined him on stage. The over excited crowd started rushing here and there.

A number of fans slipped into faint  and they had to be carried out by security guards.

"(It) was complete pandemonium. Six people were carried out after hyperventilating. They literally fainted when Britney walked onto the stage where Nicki was hanging," said a source.