‘I wasn’t born to play anything really, but for a plethora of reasons this is a very important moment for me as an actor. Howard Marks is a great friend and a great Welshman. We got to know each other in 1995/96 through a band called the Super Furry Animals, I wasn’t actually in the band when we met, I was sleeping on the drummer’s floor. I was there for the year when Howard started working with the Super Furries – that’s when we bonded.

Officially the film became possible about two years ago. Between me and Howard it was on the cards from the night we met. But when we met I wasn’t an actor and he wasn’t an author, he was a drug dealer and I was a drug user [laughs]. It was thirteen years of preparation for this role. When I got the role it wasn’t a case of “I’d love to spend some time with Howard Marks” because I’ve known him for so long it was kind of osmosis as opposed to diffusion.

This is a unique situation for Howard and myself; can you imagine what it is like to have a film made about you and to be played by a friend? It was a very natural film for us to work on.

For me this film is a journey – an odyssey in classical terms – that’s the arc of it. As an actor, that’s what you are presented with and what you work with. Of course, the fact that I am Welsh is a huge factor in why I wanted to make this film. I’m a passionate Welshman, I have a culinary relationship with language, I taste what I say because I have two languages and each informs the other.

Usually in films like this, if the guy you are playing turns up on set it’s a big thing, but with this film it was totally normal. We just laughed at how much we looked like each other. Howard spent all the time laughing at my wig.

When you act you’ve got to be like a poet or a musician. It’s not about evidence before court, it’s not a forensic subject, it’s poetry, it’s a completely different place. I immerse myself completely in research, but I’d say I’m more of a methadone actor than a method actor [laughs and phone buzzes]. Hold on a minute that’s my lawyer.’ (Interview by Paul Dale)

Mr Nice, general release, Fri 8 Oct. See review.