Lady Gaga's surprise London appearance

Lady Gaga's made a surprise performance at the 02 Academy.

No, we're not talking about her Monster Ball gig at the O2, but her appearance on stage with Semi Precious Weapons at the O2 Academy Islington 2.

The group are supporting the Bad Romance star on her current Monster Ball UK tour - performed at the O2 Academy 2 in Islington.

GaGa dressed in a bra and a pair of leather trousers duetted on two songs and also played drums during the show, before stage diving into the crowd.

GaGa wrote on her Twitter: "London, I have never felt more grateful for little monsters, music, and creativity. I can't wait to blow the roof off the O2 Arena tonight."