Prince William is celebrating his 30th birthday with a "private and low-key" party.

Britain's Duke of Cambridge is believed to be toasting the milestone today with family members and close friends.

Rumours had been circulating that the Duchess of Cambridge was planning a secret party for her husband with the help of their close friend, nightclub owner Guy Pelly.

However, palace officials released a statement that hinted at a much quieter celebration.

"He'll be spending it in a low-key, private fashion," St James's Palace commented.

William stands to inherit an estimated 10 million fortune from his late mother now he is 30.

Princess Diana reportedly amassed an estate worth over 12 million after tax deductions; to be split equally between her two sons William and Harry.

Thanks to shrewd investment, it is said to have grown to around 20 million.

Meanwhile, it has been reported that Catherine has put together a thoughtful collection of gifts for her husband.

She is said to have made a scrapbook with memories of their relationship and put together a playlist of their favourite songs as a couple.

"Thank you for all of your birthday wishes to The Duke of Cambridge today!" Clarence House tweeted earlier today.