Tim Welbourn, of South Croydon, was among 300 lucky members of the public to tour the Olympic Stadium two weeks ago.
Mr Welbourn won a competition to get his place on the first public visit to the site.
He said he had always been curious about what goes on and how they create something so big.
He said: "Having seen it firsthand, I'm really looking forward to the Games."
Mr Welbourn, who brought along guest John Lavabre, went home with a commemorative silver coin marking three years to the Olympics, one of four designs to be produced in the run up to the games.
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