|Styles performing with One Direction|
The 'Live While We're Young' star's friend has told how they used to cause trouble in supermarkets and pretend he had Tourette syndrome - a condition which makes sufferers shout out things at random - as teenagers.
Childhood pal Will Sweeney told The Sun newspaper: "We'd act like complete idiots in public. Harry would go into [British supermarket chain] Tesco, pretend he had Tourette's and walk around screaming and shouting.
"We'd throw things at each other, we'd just create chaos and a bit of a mess. We were told off by security and customers.
"We played this game where you pick something up and launch it over your head without knowing where the other person is - and they've got to try to catch it.
"We grabbed all sorts; bread, sauces, and Harry dropped stuff everywhere.
"Harry loved it. He was always up for fun, wacky things, having a laugh, and he never cared what people thought."
Will has previously admitted the 18-year-old heartthrob's carefree attitude has always meant he's been a hit with the ladies.
He said: "Groups of girls warm to him because of his personality and cheeky-chappy style, so we always used to wind him up and just say, 'Classic Styles'. He's really easy to talk to - if you met him in the street, you wouldn't feel intimidated."
Harry - famous for dating older women - has recently said he is looking for a girl with a similar attitude to himself.
He said: "I'm looking for a girl who's cheeky and will make me chase her. The fun's all in the chase."