Britain's Prince William might be perfectly poised now as he reaches his 30th birthday, but back when he was a child he was a right royal handful at times, this according to a new biography to be published this week in the U.K. by royal scribe Penny Junor.

Titled Prince William: Born to be King: An Intimate Portrait, Junor recalled one amusing incident during William’s youth when he interrupted a meeting his father Prince Charles was having with Irish musician and humanitarian Bob Geldof.  Wills was apparently none too pleased with the company his dad was keeping.

“Once, William barged into a meeting his father was having with the habitually disheveled musician Bob Geldof,” Junor writes. (It’s true that most days Geldof looks like he rolled out of bed and straight out the door.)

“‘Why do you have to talk to that man?’ (William) demanded. ‘Because we have work to do,’ said his father.

“‘He’s all dirty,’ said William.”

Geldof apparently lost his cool with the cheeky child.

“‘Shut up, you horrible boy,’ said  Geldof,” Junor wrote.

“‘He’s got scruffy hair and wet shoes,’ said William, undeterred. ‘Don’t be rude,’ said Charles, mortified.”

Though Wills and Geldof have likely met since those childhood days, the Irish philanthropist is still friendly with Charles and his wife Camilla Parker Bowles.