It is the role of a lifetime, a starring performance for which there is always top billing.

“Coming into school, I find myself stepping into role,” said Neil Craven.

“Monday to Friday, 9am to 3.30pm, I’m Mr Craven, primary teacher. The rest of the time, I’m someone else.”

His ideal role would be the Ewan McGregor part in Moulin Rouge. Instead, he is one of 26 performers shortlisted for the second round of Musicality, a Pop Idol-style search for a West End singing star.

Almost 2,000 chorus-line hopefuls danced and trilled their way through staples of the musical theatre for the Channel 4 series. The shortlisted performers then spent a weekend being trained by industry professionals.

All were competing to spend three months being tutored for a one-off performance at a West End theatre.

Mr Craven, from St Andrew’s Major Church in Wales primary, in Dinas Powys, Vale of Glamorgan, was one of four teachers on the shortlist. He believes that the classroom is the perfect preparation for the audition room.

“When I teach children Welsh, I often set things like the days of the week to music,” the 25-year-old said. “Music tends to appeal to them. And you prepare for a lesson as you would for an audition. You adapt the role as necessary.”

Denise Hodgkiss, Year 6 teacher at St Catherine’s prep school, in Guildford, Surrey, agrees that a captive audience of 11-year-olds is the perfect rehearsal opportunity for her burgeoning musical ambitions.

“When you’re teaching, it’s a performance,” she said. “Children are so used to multimedia, that pure chalk-and-talk teaching doesn’t engage them. You have to think of other ways of grabbing their attention.”

For Ms Hodgkiss, 52, these include bursting into a hushed English lesson and belting out a full-length rendition of “The Sound of Music”. She has also powered her way through “The White Cliffs of Dover” during a lesson about World War Two.

Kerry Newton, 32, science teacher at Stanney high, in Ellesmere Port, in Cheshire, similarly believes that years in the classroom helped to prepare her for the stage.

“Before I trained to be a teacher, I was quiet and shy,” she said. “But years of standing in front of a class really helps your confidence.”

Nonetheless, Matthew Goodgame, a primary teacher at St Saviour’s Church of England junior in Westgate-on-Sea, Kent, and one-time am-dram Bernardo in West Side Story, believes his pupils will be surprised to see him warbling his way through “On The Streets Where You Live” on their TV screens.

“Pupils think that teachers live in the stock cupboard,” he said. “They don’t realise we have lives of our own.”

Mr Goodgame became a teacher because he felt the profession offered necessary security. “In 10 or 15 years’ time I might not be able to do the splits, leap about or sing as well,” the 24-year-old said. “But I will teach just as well. Possibly better, because I will have more world experience.”

Ms Newton was similarly tempted by the structured career path of teaching.

But, after 10 years she has concluded that teaching is no business like show business, and moved to supply teaching to focus on her stage career.

“I’m a bit of a drama queen,” she said. “But you can’t do a dance routine in science lessons. The Bunsen burners get in the way.”