Blair Dunlop has faced two opening nights in his short acting career, but he has no doubt which one has been the more nerve-racking.

Earlier this year, the 13-year-old attended a star-studded cast viewing of Charlie and the Chocolate Factory, in which he played the role of a pre-pubescent Willy Wonka.

The screening, at Pinewood Studios in Shepperton, Greater London, was also attended by his better-known co-stars, Johnny Depp and Helena Bonham-Carter, along with Tim Burton, the film’s director.

But it is his second opening night that prompts the most nail-biting. This month, Blair will take the lead in the annual play at his Derbyshire private school.

“Without a shadow of a doubt, I’m most nervous about the school play,” he said. “Charlie was about watching something you’d already done. This is for real.”

Blair arrived at pound;6,675-a-term Repton school in September a minor celebrity. As Johnny Depp’s younger alter-ego, he appeared in the film weighed down by head-braces and a dictatorial dentist father.

“Yeah, a few people asked for my autograph,” he said. “And girls ask me all the time what it was like working with Johnny Depp. I wind them up and say we’re really good mates. Starting at a new school is more daunting, though, than being in a film. You’re coming in at the bottom. Eighteen-year-olds can be huge, and I’m not the biggest. But being in a film helped me settle in, rather than hindering me.”

When he started at Repton, Blair was initially concerned with trying out for the school’s under-13 football team.

His decision to audition for The Ragged Child in his first term was based largely on a sense of duty. As the recipient of a drama scholarship, he felt he ought to give it a try.

“Comparing film and stage is like comparing sports and ceramics,” he said.

“They’re totally different. In film, if a take doesn’t work, you’ll have another go. On stage, you only have one go. And films are really just about looks, rather than acting ability. In the theatre, you need to be comfortable in front of an audience.”

Guy Leavesley, theatre studies teacher at Repton school, says Blair affects no pretensions to expertise.

“You could have three guesses which one he is, and you’d probably get it wrong every time,” he said.

“But he’s eminently directable. He can discuss moves, and ask if something’s right.

“A lot of children can’t, but this is very much a school show. I don’t feel he’s comparing me to Tim Burton.”

Similarly, 16-year-old Edwin Hillier is not intimidated by his more famous Ragged Child co-star.

“Blair doesn’t brag about it,” he said. “Obviously, he’s got a lot of potential, but he’s pretty inexperienced on stage. Anyway, there’s other things to discuss - how the play is going and, you know, life.”

Neither is Blair tempted to make comparisons. He says he has much to learn from his seasoned colleagues.

And, he adds, even his Hollywood co-stars had flaws.

“Freddie Highmore, who played Charlie, was really nice,” he said. “We hung out and played PlayStation games. But he was an Arsenal fan, and I support Spurs. The friendship could only go so far.”

adi.bloom@tes.co.uk