Justin Bieber Hints At Special Guest During Summertime Ball 2012 Performance

9 June 2012, 10:03 | Updated: 9 June 2012, 21:44

The 'Boyfriend' star says he's also looking forward to catching up with mentor Usher at Wembley Stadium.

Justin Bieber has hinted that a special guest may join him during his appearance at the Summertime Ball in London tonight (9th June).

Fans of the 'Boyfriend' star are currently assembling outside Wembley Stadium – more than six hours before the show is due to begin.

Justin took to Twitter this morning to say how excited he was about performing at the event, which will also see his long-time friends Usher perform.

"Me and big bro @usherraymondiv gonna kill it 2nite at Summertime Ball here in London," he wrote.

The singer then surprised his followers by adding: "Got a special guest with me too."

PHOTOS: Justin Bieber's Best Moments In Pictures.

Speculation is now growing at Wembley as to who may join the 18-year-old superstar tonight.

Justin Bieber performing with Usher at the Summertime Ball two years ago: 

Today's Summertime Ball will also feature performances from the likes of Coldplay, Katy Perry, Jessie J, Ed Sheeran and Example.

Find out who joined Justin Bieber at the Summertime Ball

The Wanted and Lawson will also perform later.

Capital FM is coming live from the Summertime Ball at London's Wembley Stadium on 9th June.

Keep your eye on the ball by heading to our Summertime Ball area for all the latest news, photo galleries and interviews from this year's event.

Don't forget that you can also follow the action as it happens by following Capital FM on Twitter and liking us Facebook.