Audience get up close and personal for Harry Potter star's nude debut

Sixty people from the audience will actually be seated on stage when the Harry Potter star, in his role as the troubled groomsman Alan Strang in Peter Shaffer's celebrated play Equus, simulates a sex act while naked and astride a horse. The play, which also stars Richard Griffiths, will be performed in the round for 16 weeks at the Gielgud Theatre on Shaftesbury Avenue, with previews starting on February 16 and an official opening night planned for February 27.

The rest of the audience will have to be content with watching Daniel, 17, from the stalls and the circle - but I predict that those 60 seats on stage are going to be the most sought-after seats in London.

Tickets will not go on sale at the Gielgud for a while. In any case, Equus will open after Frost/Nixon, which is being transferred from the Donmar Warehouse Theatre, completes a limited run.

John Napier, the awardwinning designer of the original production of Equus four decades ago, has been lured from his studio in East Sussex by producer David Pugh to create a set for the new production, which will be directed by Thea Sharrock.

The nude scene was a coup de theatre in the original production when Peter Firth (spy chief Harry Pearce in the brilliant Bafta-winning Spooks on BBC television) played the Alan Strang role. Firth also did a screen version with Richard Burton.

Radcliffe, who is finishing work on Harry Potter And The Order Of The Phoenix, shooting scenes with Ralph Fiennes as the evil Voldemort, has been studying the play for more than a year.

The Daily Mail was the first to reveal that the teenager was considering making his dramatic debut on the London stage - although at the time no one realised just how dramatic his performance would be.

In the play, Strang is institutionalised for blinding six horses with a groom's spike. Griffiths will play Martin Dysart, a psychiatrist who begins a psychological and spiritual investigation into what drove the young man to commit the cruel acts.

Griffiths, who has shed three stone in weight, recently completed a sellout run on Broadway with the original National Theatre cast of Alan Bennett's The History Boys.

The movie version opens in cinemas today and Griffiths is tipped for possible Orange, Bafta and Academy Award nominations for his performance.

He and Daniel know each other well: he plays Harry's horrible Uncle Vernon in the Potter pictures.

Director Sharrock and producer Pugh will cast the remaining Equus roles over the next few weeks and begin rehearsals on January 3.