The pictures were allegedly taken in December 2002 - before Prince William began dating fiancee Kate Middleton - at a 21st birthday bash organised by the royal's pal James Tollemache.
A man, who bears a striking resemblance to the groom-to-be, is shown soaking wet after jumping into a moat at a country estate in Suffolk, England and dancing in his boxer shorts wearing a purple feather boa, while a girl ties a pink corsage around his waist.
The photographs, obtained by Britain's The People newspaper, are said to have been taken while the prince was enjoying a break from university.
A party goer tells the publication, "He was cool about stripping off and really going for it... He was having a boogie (dance) in his pants and a couple of feather boas. It shows how popular he was. Wills wasn't a big boozer - these were just high jinx."