Britain's Prince William and his wife Catherine, Duchess of Cambridge, are seen at the Olympic Stadium during the London 2012 Olympic Games August 4, 2012.

Britain’s Prince William and Prince Harry were kept “in the dark” about their grandmother’s cameo at the Olympics.

Queen Elizabeth made a surprise guest appearance alongside James Bond at the opening ceremony of the London event, and her grandchildren were as surprised as the rest of the world when they saw her involvement.

Speaking in an impromptu interview with BBC presenter Sue Barker, William said: “To be honest, we were kept completely in the dark about it. That’s how big the secret was. She did such a good performance that she has now been asked to star in the next Bond film.”

Harry added: “You don’t expect the Queen to do something like that.

What she does in her spare time is her spare time!”

The royals have been spending a lot of time at the Olympic Park in Stratford, East London, and William was recently spotted in an embrace with his wife Duchess Catherine when the British team won a gold medal in cycling – although he admits he was nervous of being picked out in the crowd by a kiss cam, where subjects are picked out and encouraged to kiss on a big screen.

He said: “I was absolutely dreading that they were going to show myself with my wife. And that would have been very embarrassing.” - BANG Showbiz