Harry Potter star Daniel Radcliffe will strip off for his London stage debut as a psychologically disturbed stable boy in Equus.

The 17-year-old, currently making the fifth Harry Potter film, will star alongside Richard Griffiths, who plays his grumpy uncle in the wizard sagas.

Radcliffe will play Alan Strang, a stable boy who is interviewed by a psychiatrist after he blinds six horses with a metal spike. In Peter Shaffer's controversial play, the role requires the actor to ride naked on his horse.

"This is an extraordinary play and, yes, there is a scene of nudity in it, but that's not what the play is about," said Radcliffe's publicist Vanessa Davies.

"He finishes shooting Harry Potter and the Order of the Phoenix in October or November and rehearsals are starting in January," she added. The play is expected to open in March.

Harry Potter and the Order of the Phoenix is the fifth J.K. Rowling book to be turned into a film. There are doubts about whether Radcliffe can continue to play the boy wizard until the end of the series.

Rowling is now writing the seventh and final book of the hugely successful series.

The first four Harry Potter films have amassed around $3.5 billion worldwide at the box office.