In a career that has seen him play a heroin addict, a glam rocker, a Jedi Master, and a English poet - among many others - Scottish actor Ewan McGregor has amassed a ridiculously diverse body of work since his 1993 debut as Alvarez in Being Human.

With his breakthrough role three years later in Danny Boyle's Trainspotting, McGregor quickly established himself as a serious and versatile actor who could carry a movie on his performance alone.

As the titular character in Roman Polanski's The Ghost, McGregor plays a writer assigned to handle the memoirs of a former British Prime Minister and discovers a shadowy plot to... well, we won't ruin it. But he did earn the honour of becoming the first Moviefone subject to successfully use the word "pernickety" twice in one interview.

In a career that has seen him play a heroin addict, a glam rocker, a Jedi Master, and a English poet - among many others - Scottish actor Ewan McGregor has amassed a ridiculously diverse body of work since his 1993 debut as Alvarez in Being Human.

With his breakthrough role three years later in Danny Boyle's Trainspotting, McGregor quickly established himself as a serious and versatile actor who could carry a movie on his performance alone.

As the titular character in Roman Polanski's The Ghost, McGregor plays a writer assigned to handle the memoirs of a former British Prime Minister and discovers a shadowy plot to... well, we won't ruin it. But he did earn the honour of becoming the first Moviefone subject to successfully use the word "pernickety" twice in one interview.

When you first were offered 'The Ghost,' were you familiar with the novel?
I read the novel after I read the script. When you get an offer from Roman [Polanski], that's one of your better days and I liked it so much, I read the book. I saw the character of The Ghost really clearly when I read him in the script and I knew that Roman had written the script with ['The Ghost' novelist] Robert Harris so I knew that they'd been involved in that together. So I trusted that it was the adaptation that they both wanted. In a way, that's perfect. You might not even bother with the book.

Were you tempted to not read it to avoid subconsciously cribbing from the book?
I have done that in the past where reading the book is just not that helpful, but I spoke to Robert about the way I wanted to play him. I would've just played him with my [Scottish] accent but Robert didn't want him to be from Scotland because of the reference to [Prime Minister Adam] Lang's family being Scottish. I still don't think it would have made much difference, but he didn't want that. But once I'd read the script, I had him in my head so I suppose that's who I saw when I read the book. I was just seeing the same guy.

In the production notes for 'The Ghost,' you say that Polanski is always giving actors interesting notes on their performances. What did you learn from him in this regard?
He's always pushing you. The first scene we shot on the first day lasted 22 hours. Just on and on and on. Whenever there's a new set or new location or new actor, it would take Roman a little while to warm up and get it in his head how we were going to shoot it. He said to Tim [Preece, who plays Roy] about one line, "When you say that line, be a little moved" and nobody quite knew what he meant. Sometimes you think with Polanski it's just a whim - just what's flitted through his head - but it was a genius note. I just found he was always pushing to find the truth. Some of the lines I delivered because they're how he wanted me to deliver them, not necessarily how I would have done it myself.

Are you worried that external events will alter how the film is perceived?
I hope not, but I don't know the answer to that question. My hope is that the film is viewed for the film's sake and the people that might not go and see it because of Polanski's situation might not have gone to see it anyway. But of course I would never dream of telling people what to do or think. That's not for me to say.

When you read the script, how much of the political message informed your decision to take the role?
When I first read it, I didn't see the bigger political picture. I was looking at it through The Ghost's eyes and I'm not political. I'm really not very interested in politicians. I just find it really boring.

Like The Ghost.
Yeah, that was quite handy. So I wasn't as aware as I am now about the political message in it but I really agree with it. I'm delighted that it says that our politicians should be answerable for their actions. There's a political relationship at the centre of the film between Lang and his ex-Cabinet Minister who's now getting him into trouble and the idea that politicians are just back-biting and not to be trusted is probably pretty dead-on.

Looking back on your role in 'Trainspotting,' what do you think Mark Renton would be doing right now?
Well, I hope he'd be clean somewhere. Probably clean. Irvine [Welsh] wrote the sequel 'Porno' and in that, Mark Renton runs a gym in Amsterdam, so...

Were you ever tempted to go back to the role?
There was talk of it, but there was never a script produced.

If I gave you DVDs of all three of the new 'Star Wars' films, which would you watch first?
[Immediately responding] The third one. I think that's the best one I made. I think the first two do a lot of setting up and the third one has more of the flavour of the original three. I wasn't a 'Star Wars' fanatic, but my uncle [Denis Lawson] was in all three of them [as Wedge Antilles] so I had a personal vested interest. But me and my brother knew all the lines to the first one and could quote them often.

You recently recorded vocals for the animated 'Jackboots on Whitehall'. Is it easier or harder when it's just your voice doing the acting?
Some of the animation is really pernickety. You had to do the same lines over and over again and I was amazed how pernickety they were about the direction. But with other things like 'Valiant'. I just read it all through once basically and that was it. With 'Jackboots,' when I got there, they went, "We'd like you to do a Somerset [county, England] country accent" and it's not an accent I'd ever done before and [in Somerset accent] "It's like this. It's really specific." So I did the whole thing in the Somerset accent and went back three years later and re-recorded bits of it.

What's the status of 'The Last Word'?
I did that up in Scotland with David MacKenzie. We made a love story set against the end of the world. For the first time, I got to act with my uncle and play scenes together so that was great.

And you got to quote 'Star Wars' lines.
[Laughs] I can safely say we never did that.