Britain's Princes William and Harry danced to the Harlem Shake at a stag do on Saturday night.
The royal brothers had a "great time" partying at Harry's friend Guy Pelly's Tonteria club in Sloane Square, central London, and father-to-be William ? whose wife, Catherine, Duchess of Cambridge, is pregnant with their first child ? took the opportunity to let his hair down ahead of some sleepless nights.
A friend told The Sun newspaper, "William was really going for it. He was dancing loads and singing along to the music. They looked like they were having a great time."
While dancing to internet sensation Harlem Shake, William waved sparklers around in the VIP area of the exclusive club.
The siblings sipped cocktails as they partied and joked around with inflatable novelty toys before leaving the venue at 1.30 am.
William was spotted slipping out of the back door of the club looking slightly the worse for wear.
Harry ? who had naked pictures of him playing strip billiards in Las Vegas surrounded by a bevy of beauties emerge online last year ? is known for being a bit of a party animal.