Prince Harry has been showing off his royal jewels, and an American celebrity gossip website has the proof.

On Tuesday, the website TMZ posted two photos of someone who looks strikingly similar to the prince playing naked pool.

The photos were taken in Las Vegas on Friday night while the prince was enjoying a personal holiday.

The website reports Harry and some friends invited some women they met at the bar of the MGM Grand to their private suite. That's when things got out of hand and the saucy pictures were snapped.

One photo shows Harry covering himself with his hands while a naked girl stands behind him.

The second photo shows the prince's naked behind and he appears to be leaning over a girl who is holding a pool cue.

Harry is known for his "bad boy" behaviours - in 2005 he wore a Nazi costume to a birthday party. In 2007, he met Cherie Cymbalisty, a Calgary bartender who, after some flirting, sold her story to British tabloid News of the World.

Other photos of the prince on vacation showed him relaxing by the pool and drinking with friends.

But the prince was apparently aware people were watching. Chicago Sun Times columnist Bill Zwecker reported Harry was overheard telling a security guard he had to be careful or else he'd end up "on Twitter or Facebook or YouTube thanks to somebody's mobile phone camera."