(Cover) - EN Showbiz - Britney Spears has described Nikki Minaj's performance on her Femme Fatale tour as "the icing on the cake".

The singer, who is currently touring the US with the female rapper as her support act, expressed her excitement about their collaboration by uploading a picture to social networking site Twitter.

The photograph shows the two stars performing on stage in Los Angeles, with Britney showing off her moves in a glittering costume while Nikki looks on, waiting for her cue.

"LA was on fire last night! One of the best crowds of my life. @NickiMinaj finale put the icing on the cake. Britney," she wrote.

The pop star has also just released her latest music video for new single I Wanna Go, which appears on her new album Femme Fatale.

In the clip, which shows the star running out of a press conference, Britney pokes fun at the media circus surrounding her.

Directed by Chris Marrs Piliero, who has previously worked with Ke$ha, she is also seen attacking paparazzi in the street with a microphone, before realising it was all a dream. (C) Cover Media