It seems Prince William is partied out! It's been a hectic 2 months for the prince and it's about to get crazier as he moves into Kensington Palace with Kate Middleton and then embarks on a tour of the U.S. and Canada where he will make a number of public speeches.

Which is probably why Prince William is spending his 29th birthday at work today.

William will spend the day at work as a Royal Air Force helicopter pilot and is said to be celebrating his birthday privately afterwards.The low-key day follows in the example of William's grandfather, Prince Philip who spent his 90th birthday doing charity work earlier this month.

The Duke and Duchess of Cambridge will embark on their first foreign tour together next week, making stops in California and Canada.