N-Dubz star Tulisa Contostavlos was involved in an alleged altercation with her bandmate Dappy's girlfriend backstage at a show on Wednesday.

The singer, who recently replaced Cheryl Cole as a judge on Britain's The X Factor, was left furious when Dappy's on/off partner Kaye Vassell accused Constostavlos' friend Nyomi Gray of having an affair with the rapper.

The pair argued behind the scenes at a gig at the O2 Academy in Oxford, England before Contostavlos ordered bouncers to remove her, according to Britain's The Sun.

A spokesperson for the band has confirmed the bust-up, saying, "There was an altercation between Tulisa and Kaye backstage at the concert. This took place in a private area away from the gig. Tulisa was upset Kaye had accused her best friend of something she hadn't done."

Dappy and Vassell, the mother of his two sons, split in March after three years of dating, only to get back together in June.