The 38-year-old winger is one of three overage players, while he will be making his first appearance at a major international tournament after a successful club career at Manchester United.
Along with Giggs, Liverpool's Craig Bellamy and Manchester City's Micah Richards are the other two overage players with Great Britain drawn against Senegal, UAE and Uruguay in Group A. In their opening Group fixture, Giggs and Co. will play against Senegal at Old Trafford on Jul 27.
Giggs, who retired from international football in 2007 with 64 appearances for wales, said its an honour to be part of Olympics and hoped his side can win a medal.
"Obviously it is a tremendous honour to be part of the Olympics," the Sun quoted Giggs as saying.
"It is a unique experience and one from the start that I wanted to be part of when I got the opportunity," he said.
"We hope we can get gold. That is what the players are hoping for. The players are winners and want to do well. You want that gold medal," the 38-year-old Manchester United legend said.
"It is going to be tough because a lot of the other nations have picked good players and have got a good team. It is going to be tough, but we have a good chance."
None of the players in Stuart Pearce's 18-man squad are from Scotland or Northern Ireland while five Welsh players have been included.
"Just like the Welsh lads involved, they're Welsh but we just wanted an opportunity to play for Great Britain in an Olympics on home turf so I think it was a chance we couldn't turn down," he said.
"It was one we're excited about and if other people want to disagree with then that's their prerogative, but as a player I am excited and can't wait," he added.
Several players including Craig Bellamy and Aaron Ramsey praised and backed Giggs' appointment as captain.
"He is probably one of the best players who has ever played the game. It is fitting he is the captain and also I have been very fortunate to play with him for my country as well, so I know Ryan quite well," Liverpool striker Bellamy said.
"Everyone knows what he has done in the game. He has been there and done it. He has won many trophies and he is a great player as well," Arsenal and Wales midfielder Aaron Ramsey said.