Usher: 'Pumped' For Summertime Ball 2012

Usher rocks shades as he signs autographs upon arriving at Langham Hotel on Friday (June 8) in London, England.

The 33-year-old entertainer is set to perform at Wembley Stadium later today (June 9) at the Summertime Ball along with fellow artists Justin Bieber, The Wanted, and Katy Perry.

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“I haven’t been able to sleep all night,” Usher tweeted. “I’m so pumped to hit the stage for Summer Ball 2012 today!!! URIV”

He later added, “Come out and dance onstage as I perform #Looking4Myself 6/11 at #AmexUNSTAGED at UsherVevo.”