The Los Angeles Galaxy midfielder made Britain coach Stuart Pearce's shortlist of 35 but wasn't selected for the final 18-man squad as one of three players over the age of 23 allowed to compete in the games.
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"Everyone knows how much playing for my country has always meant to me, so I would have been honored to have been part of this unique Team GB squad," the 37-year-old Beckham said Thursday in a statement to The Associated Press. "Naturally I am very disappointed, but there will be no bigger supporter of the team than me. And like everyone, I will be hoping they can win the gold."
Beckham had been widely expected to be selected for the Olympic squad after playing an instrumental role in in helping Sebastian Coe and his team win the bid in 2005 to host the games.
"As a Londoner, I will have been really proud to have played a small part in bringing the Olympics to my home town as part of Seb's team, and I can't wait for the games to begin and enjoy every moment along with the rest of Great Britain," Beckham said.
Britain's three overage players will be Welsh stars Ryan Giggs and Craig Bellamy and English defender Micah Richards, a person familiar with the situation said. He spoke to the AP on condition of anonymity because details of the squad haven't been publicly released.
Giggs played alongside Beckham at Manchester United and Bellamy is a forward at Liverpool. Richards plays for Manchester City and appears to have been chosen ahead of Beckham to provide extra defensive cover.