Prince William recently celebrated his 30th birthday

Prince William marked turning 30 by downing flavoured vodkas, Now can reveal.

The Royal took wife Kate Middleton and 30 friends out for a belated birthday bash at Russian-themed restaurant Mari Vanna in Knightsbridge on 2 July.

And it seems the booze was in full flow, as a fellow diner tells Now: 'He and his mates were clearly enjoying a good party.

'Wills definitely looked the worse for wear after enjoying a few flavoured vodkas.'

Things got interesting when the guests gave William, who turned 30 on 21 June, his gifts - one of which was an apron featuring a male model's ripped body in blue trunks.

Another onlooker says: 'He clearly loved it. He was still wearing the apron when he came out into the smoking area at 3am... It must've been one hell of a party!'

There was one person in less of a party mood, though.

Kate, 30, decided on an earlier night, leaving at 1am while William stayed on until just after 3am and is thought to have continued the party at a friend's house.

Read more about Prince William in Now magazine dated 16 July 2012 - out now!

MORE PICTURES Amazing facts about Kate Middleton - Prince William's wedding belle>>


SEE PICTURES Kate Middleton and Prince William: Their love story in photos>>

ROYAL WEDDING GALLERY See the guests arrive for Prince William and Kate Middleton's special day>>