The Duke of Cambridge has said he could only imagine how it would feel to compete in the Olympic Games, and told British competitors: "Glory awaits you."
In a speech at a star-studded gala dinner at the Royal Albert Hall, William said: "You, our Olympians and Paralympians, will inspire people up and down this country, and far beyond its borders."
The event, named Our Greatest Team Rises, featured an energetic performance from dance group Spelbound, who won Britain's Got Talent in 2010. Take That singer Gary Barlow, artist Will Young and singing sensation Alfie Boe were among the other acts set to perform in honour of the sportsmen and women.
William and Kate were greeted by Lord Moynihan, chairman of the British Olympic Association, before attending a pre-dinner reception to meet gold medal winners and Team GB ambassadors, including Sir Steve Redgrave, Dame Kelly Holmes and Denise Lewis.
Sir Steve said: "Over the last few years they've been top of the world's publicity so having their support really makes a big difference."
The Duke said: "For the athletes of Our Greatest Team, these Games mark the pinnacle of your sporting careers. I can only imagine it, competing at home in front of your countrymen and women, with the eyes of the entire world upon you. A dream come true.
"For all of us mere mortals, and I include my brother, who still drones on about beating Usain Bolt - which never counted because it was a false start - this is a lifetime opportunity. We will witness an exceptional moment in our island history. The mood in London will be electric, ecstatic and amazing. I simply can't wait."
He joked that he had been invited to take part in the Games, but said London 2012 chief Lord Coe did not have enough faith in him. "Naturally I was asked to compete for Team GB in every sport, but sadly Lord Coe said there were London pigeons with more athletic prowess than me," he said.
The Duke said London should take "huge pride" in becoming the only city to host the Games three times.
In a pre-recorded message played on a giant video screen, David Cameron called on everybody to "shout ourselves hoarse" in support of Team GB during the Games. The Prime Minister said: "In less than three months time all of the eyes of the world will be on the United Kingdom... Every javelin that's thrown, ball that's hit, hurdle that's jumped, we've all got to shout ourselves hoarse, willing on Team GB to win. Every day of these Games we've got to come together to show the best of this, our country."