Star Wars and Trainspotting actor Ewan McGregor tells Steve Pratt about how he came to find himself in the psychiatrist's chair.

Trainspotting and Star Wars actor Ewan McGregor found himself in the psychiatrist's chair thanks to the thriller Stay. He plays a shrink in the movie from Finding Neverland and Monster's Ball director Marc Forster, so he researched by meeting a couple of psychiatrists - a man and a woman - in New York, where the action takes place.

He found his foray into their world a fascinating one. "It's very interesting anyway, but seeing it from their point of view is really interesting," he says.

"The idea if you see a therapist or a psychiatrist is it's very much about you. You don't really think about it from their point of view, nor should you actually.

"But when it was my job to think about it from that point of view, it was quite interesting to see that. Both of them have said this, that many psychiatrists have problems themselves, have issues themselves and that's why they're in this.

"They get into it because they feel the need to help lots of people. And why's that? Because they need a lot of help themselves."

Stay is being released on DVD in the uncut version, billed as "the version they wouldn't let you see at cinemas".

In fact, very few people saw it on its limited release. Stay is one of those films that, despite a decent cast and director, remained on the distributor's shelf and then, when finally released, only shown in a handful of cinemas.

McGregor admits it was a weird film to make, partly because he'd never made a film in New York City before. The schedule involved much night shooting which added to the oddness.

"That always immediately makes the experience very weird because you're sleeping during the day. Can you imagine trying to sleep during the day, especially in New York? My curtains, my windows were all blacked off for week. Then trying to sleep during the day with the noise of New York."

Another difficulty were the shooting conditions themselves. Rather than block off areas for exclusive use by film-makers, they were filming on the streets among the public.

"Usually in a film you'd move into a street and the ends are blocked off, it's just us in the middle, we take over. But in New York, you're filming among the city and its people, and they don't get out of the way. And you say, 'sorry, we're filming' and they're like, 'eff off'. So you're just stuck in the middle of it.

"It's a weird thing and then, of course, it's a very bizarre story and Marc was quite experimental in many ways, so it was weird, brilliant."

McGregor's screen shrink stands in for a colleague, taking over the case of a troubled young man (Ryan Gosling) who announces that he intends to commit suicide at midnight on Saturday.

Naomi Watts, the beauty menaced by the beast in the recent King Kong remake, co-stars as the psychiatrist's girlfriend and former patient.

"The film is basically about my struggle to stop him and his struggle to do it," says McGregor.

"I start breaking the rules of psychiatry by trying to find him outside of the office and stop him.

"It becomes very important to me to save his life and, while I'm doing that, my reality starts to crack and things spiral kind of out of control for my character."

He hopes the unusualness of the thriller won't deter audiences.

"I think it's a satisfying movie because it unravels in front of your eyes, you have to do a bit of work yourself," says McGregor.

"It's a clever film and I think Marc tried to fool an American studio into making an experimental movie, which is kind of what he's done - and he's done it very well,"he says.

* Stay is released to buy and rent on DVD from Twentieth Century Fox Home Entertainment on July 3.