Video! Lady Gaga Rehearses for the iTunes Festival

Superstar Lady Gaga will be performing at the iTunes Festival in London, starting Sunday, September 1.

Check out her rehearsal!

Running every night in September at the Roundhouse, the iTunes Festival features over 60 acts performing at the legendary venue.

Other artists include Justin Timberlake, Thirty Seconds to Mars, Jack Johnson and Jessie J.

Performances can be watched live or on-demand by millions of iOS users around the world on their iPhone, iPad or iPod touch, along with music fans with iTunes on their computer or in stunning HD with Apple TV. Tickets are free for competition winners only.

For more information, go to the official website!