The surprise appearance of pop star Britney Spears became a subject of bedlam at R&B star Nicki Minaj`s party as the security guards had to struggle with the over-excited crowd of fans to keep them in check.

Minaj, 26, held the stage for a party at The Factory venue in West Hollywood on Friday night after her performance with Lil Wayne at the city`s Staples Center.

Spears too made an appearance at the event and joined Minaj on stage which unfortunately created havoc among fans resulting in some of the people fainting. The fainted people had to be moved out by the security guards.

According to the source, “It was complete pandemonium. Six people were carried out after hyperventilating. They literally fainted when Britney walked onto the stage where Nicki was hanging.”

“People were crowd surfing to get to the stage. Screams were so loud for Nicki and Brit you couldn`t hear the music. Bouncers couldn`t hold the crowd back.”

Spears wrote on Twitter about her party with Minaj. She wrote, “Hanging with my girl Nicki Minaj at her after party at The Factory. Love you girl. – Britney.”

The “budding friendship” grew as the two paired in the studio to record a remix of ‘Till the World Ends.”

The number also features Kesha who co-wrote the song.