Knocking knees betray William's pre-wedding nerves.

Britain's Prince William has admitted to feeling nervous and daunted as he looks forward to his wedding to Kate Middleton in four weeks' time.

However, William, son of heir-to-the-throne Prince Charles and the late Princess Diana, said he had managed to "outfox the media" and have a stag party away from the prying eyes of the press.

Asked what was worrying him most about the wedding, William, 28, laughed and said: "The whole thing.

"I was telling everyone I did the rehearsal the other day and my knees started tapping quite nervously," he told reporters in comments broadcast on Friday.

"It's quite a daunting prospect but very exciting and I'm thoroughly looking forward to it but there's still a lot of planning to be done in the last four weeks," he added.

About 1,900 people -- from family and friends to foreign dignitaries, diplomats, soldiers and charity workers -- have been invited to the service in Westminster Abbey on April 29.

During the ceremony, William will place a ring on Middleton's finger but she will not do the same to him, because the prince has decided not to wear a wedding ring once he is married, a royal spokeswoman confirmed.

A worldwide television audience of hundreds of millions is expected to tune in for Britain's biggest royal occasion since Charles' ill-starred wedding to Diana three decades ago.

GRANDPARENTS VISIT

William was interviewed at the RAF base in north Wales where he works as a search and rescue helicopter pilot.

Queen Elizabeth, wearing a red coat and matching hat, and Prince Philip paid their grandson a visit there on Friday, listening as he explained what his job entailed in a hanger next to a yellow Sea King helicopter.

Also on Friday, the Ministry of Defense outlined the role the armed forces will play on the day of the marriage, when tens of thousands of people are expected to line the streets of London to catch a glimpse of the young couple.

More than 1,000 military personnel and musicians will line the route from Westminster Abbey to Buckingham Palace, the queen's London residence, drawn from the Royal Navy, Royal Air Force and Army.

All three services will also be represented in the "Path Lining Party" greeting the couple when they leave the Abbey, including people with a personal connection to William.

There will be a fly-past over Buckingham Palace by World War Two-era Lancaster, Spitfire and Hurricane planes followed 30 seconds later by two Typhoons and two Tornado GR4s in box formation.

William told reporters that he and Harry, his younger brother who served on the front line in Afghanistan, had pulled off an undercover operation for his stag do.

"It's quite good news always to outfox the media but it was a military operation and my brother and I are very proud of how it went," he said.

He laughed off questions about how bad a hangover he had suffered after the traditional bachelor party.

Harry said on Thursday that he never thought that William would take the plunge and marry long-term girlfriend Middleton.

William said he and Middleton enjoyed a low-profile existence on the isle of Anglesey.

"The beach is here and the general life is great to settle in and knuckle down to a proper job. We are left alone, it's good," he said.