HE may have found huge success as a solo artist, but ex-One Direction star Harry Styles is clearly just a kid at heart.

In his latest music video Kiwi, the singer can be seen having a cake fight in a gym with a gang of children, including five-year-old Oliver Ravelin from Bournemouth.

Oliver's mum, former professional West End star, Jamie Lee Mason, said her son, who has been dancing since he was three, had no idea who he was going to be performing with when he went for the audition in London.

"He has starred in adverts for companies like Boots before, but we were told this was an audition for a top secret pop video. When we had confirmation the following week that he had got the job, we still didn't know who it was for.

"I only found out when I had to sign a confidentiality agreement. Oliver's a massive One Direction fan so I couldn't tell him because he would have told the world.

"When I did eventually tell him the night before, he didn't actually believe me at first!"

Jamie who runs her own theatre school based at Leaf Studios in Bearwood, said after they had finished filming, Oliver got to meet the 23-year-old pop star.

"Oliver was meant to be in a scene at the end with some puppies, but because they were running really late, he didn't get a chance to do it so Harry took Oliver by the hand and walked him across the set to meet the puppies."

Jamie adds: "Harry was the nicest gentleman. When we first arrived he shook everyone's hand - I think all the parents were a bit star struck.

"There were about 25 children involved. He spent lots of time with Oliver because he was one of the youngest. This week we got a letter from him in the post with a signed poster."

Oliver who is a pupil at Epiphany Primary School, and hopes to follow in his idol's footsteps when he's older, said: "He was really nice. All the older girls at school were very jealous!"