The Pussycat Dolls and Lady GaGa united at a concert in London last night.

Nicole Scherzinger and fellow dolls Melody Thornton, Ashley Roberts, Jessica Sutta, Kimberly Wyatt and Carmit Bachar looked incredible in their racy stage outfits when they performed live at the O2 arena in front of thousands of screaming fans.

But Lady GaGa could have easily passed as the next pussycat.

Nicole sings lead vocals (left, WENN.com) and Lady Ga Ga stands out (right, Splash News)

Dressed to thrill in pink heels and a black low-cut cocktail dress, the Let's Dance star performed as a supporting act for the girls.

She then headed off to Punk for a D.J set before meeting up with Mark Ronson at Roxy.

See the girls on stage below