It was a breakout role that made him a household name as he played a drug-addled heroin addict in Scotland.

Now, 30 years on from the release of Trainspotting, Ewan McGregor has said he felt a duty to give a good performance in the film after meeting a group of ex-users during his preparations for the role.

McGregor, who played addict Mark Renton in the film, said he put a lot of care into getting the scenes right.

Marking the 30th anniversary of the film, McGregor recounted how the cast and crew worked with an ‘amazing group of mainly men’ from the Calton Athletic Club in Glasgow and the duty he felt to them as a result.

He told People magazine: ‘They were a group of ex-users, ex-heroin addicts who recovered together.

‘And they had a football team, and they were hence the Athletic Club.

‘We went to a meeting with one of them, listened to some addicts talking about coming off the drug, and we had an advisor on set who was our drug advisor.’

McGregor said he ‘tried to imagine what it would be like to be in withdrawal,’ but admitted he didn’t know what it was like ‘physically’.

He added: ‘So that was quite a stretch, I suppose. I always wanted to do it justice. Because we met these real heroin addicts, and I felt like we had a responsibility to them to get it right somehow.’

The movie is based on the best-selling novel by Irvine Welsh. Along with McGregor, it starred Ewen Bremner, Jonny Lee Miller, Kevin McKidd, Robert Carlyle and Kelly Macdonald.

The year after McGregor played drug addict Renton, he landed the megastar role of Obi-Wan Kenobi in the Star Wars prequel trilogy, securing him A-list status.

Meanwhile, Macdonald, who played Diane, went on to win a role in the Oscar-winning No Country for Old Men; Ewen Bremner (Spud) had parts in Black Hawk Down and Pearl Harbor; and Robert Carlyle carved out a glittering career in TV and films such as The Full Monty.