He plays troubled stablehand Alan Strang and is involved in a lengthy nude sex scene with former Holby City actress Joanna Christie.

Radcliffe was clearly keen to impress with his physique, pumping up his slender frame in the gym for seven hours a week.

But whether his young fans will be impressed by his transition from Hermione Granger's boy wizard friend to hunky sex symbol remains to be seen.
 

Websites were receiving e-mails from parents worried about Radcliffe's appearance in the play, which will be open to children despite its explicit adult content.

One said: 'We as parents feel Daniel should not appear nude. Our nine-year-old son looks up to him as a role model. We are very disappointed and will avoid the future movies he makes.'

Another wrote: 'I am curious as to how and why his parents said this was okay.'

The play opens at the Gielgud Theatre on February 27 and has already attracted advance bookings worth £1million.

Radcliffe has been rehearsing his nude scene for a week with his female co-star and although he was 'a little hesitant and shy' at first, he had overcome his embarrassment, said producer David Pugh.

He added: 'Equus is on the school syllabus and I would never stipulate what age people should be to see it.'

Radcliffe's spokesman Vanessa Davies said: 'Daniel does not want to step away from Harry Potter but he does want to show he is an rounded actor capable of very different and diverse roles.

'He has tremendous support from Harry Potter fans.'

Equus opened in the West End in 1973 to huge controversy. It was followed in 1977 by a movie version in which Peter Firth played Alan and Jenny Agutter played his girlfriend Jill, both appearing full frontally nude.

Miss Agutter also features in the 2007 version - as a judge with her clothes on.