Usher is joined by Justin Bieber and Will.i.am

The RnB superstar brings his performance to a massive climax at the Summertime Ball.

We said that there were a few surprises in store at the Summertime Ball and it doesnt get much bigger than this. At the end of Ushers hit-packed set, the RnB superstar wheeled out Black Eyed Pea Will.i.am and Justin Bieber to help out on his song OMG.

For a show barely twenty minutes old, Wembley's stage was graced with three of the worlds biggest music stars. Quite how Ke$ha is going to follow that, we dont know, but if her claims of getting naked with Dizzee Rascal can be believed, we wouldnt bet against a show-stealing performance.

Read more about Ke$ha's plans for the Summertime Ball.

There are many, many more surprises in store. Keep checking back for more news.