Imagine being a male film star these days. It must be rubbish. Because even when you reach that bit of life we call middle age you still can't let yourself go. You can't spend your days and nights in the bar. You can't decide to live up to the example of Peter O'Toole or Oliver Reed. Hard drinking or extra portions of caramel apple pie are not conducive to the current slim line model of the Hollywood leading man.

To be a modern movie star, quite frankly, you need to be fit. In all senses of the word. Because you never know when you're going to be asked to take your shirt off. And when you do, you don't want anyone saying "No, actually, put it back on."

That's not something likely to happen to Dougray Scott any time soon. I can't say I have visual evidence of his six pack (It wasn't that kind of interview frankly. Maybe if we'd had another 10 minutes), but it's fair to say that at the tail end of his 50th year on the planet he isn't yet following the Orson Welles or the Marlon Brando diet plan. "They didn't give a f***, did they?" he laughs. "You kind of admire that."

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Admire, perhaps, but not emulate. That probably wouldn't go down well with prospective employers. Or himself for that matter. "It's not so much about vanity or film projects. It can be about that. If you're playing someone and you have to take your shirt off you've got to look good. But mainly for me, if I'm not exercising I feel messy. I feel dirty. I don't feel right. I think staying fit is good for my head."

Yeah, but not for your waist, Dougray. You haven't got one. "I'm not overweight," he agrees. I could probably help you out there, I say. "Hah. Sometimes my diet goes out the window but when you're working you have to be quite strict."

When he's working? The question is when he's not. We're in Edinburgh to talk about a new film The Rezort (think zombie shoot-em-up). As you read this he's got another – London Town – playing at the London Film Festival. And then there's his TV work. There appears to have been a lot of that. Basically it would probably be quicker to count up the number of days this year he hasn't been on a set.

"I've been busy," he allows. "I started off the year doing this 10-part series in LA, Full Circle, about this senator who is running for President. Then I did Fear the Walking Dead."

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More zombies. It's almost a theme. Sorry, I'm interrupting. On you go Dougray.

"Then I did this mini-series Harley and the Davidsons set in America but filmed in Romania, about the birth of Harley Davidson." Scott plays the head of the rival Indian Motor Company who was, in the TV series anyway, "a bit of a dick".

After Edinburgh he's got a part in a new psychological drama for the BBC entitled The Replacement, alongside Morven Christie and Vicky McClure. And IMDB says he's also in something called Snatch. At this rate he wouldn't have time for a double-fried fish supper even if he wanted one.

I have to ask, Dougray, do you live to work? "I have to be working," he agrees. "I get kind of rattled if I'm not working."

"I develop stuff as well and that takes time. I've been developing this CIA thing with Televisa in the USA and we thought we'd be filming now but the scripts weren't quite right, so that's taking time.

"But I love acting. I never tire of it. I wouldn't say I'm more passionate now because I was really passionate when I first started out. But I certainly understand it more than I did in the beginning."

The beginning for the Glenrothes-born actor was back at the start of the 1990s when, after cutting his teeth on the stage, he started turning up on our screens in bit parts in Lovejoy and Taggart. He first came to prominence in the TV drama Soldier Soldier and before long he was adding his brooding Caledonian handsomeness to just about everything. One year he'd be romancing Drew Barrymore in Ever After, then pulling villainous faces at Tom Cruise in Mission Impossible II the next (but one).

"There was never a plan," he says. "The only plan I ever had was to act. It wasn't to be in big Hollywood movies. I wanted to be in movies but, really I was interested in independent films and I wanted to do theatre. I haven't done enough theatre."

The Hollywood movies came along though. In fact, he could have had more of them. After Mission Impossible II he was set to play Wolverine in the first X Men film but the Cruise movie took longer than expected and Hugh Jackman got the part. As a result Scott possibly missed out on superstardom.

But he's hardly been twiddling his thumbs since. In The Rezort he plays a zombie hunter at a resort where tourists come to shoot chained up zombies. (Guess what? It doesn't go well).

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He's the nearest thing the film has to a hero. His character also doesn't have much to say for himself. "I've got 10 lines in the whole film," he admits. "That's kind of cool, though. He's a very enigmatic guy. I thought that would be interesting to play."

Bit of a stretch that, isn't it? "Playing enigmatic? Yeah. I'm not," he says, laughing.

The plot is a bit Westworld and a bit Jurassic Park, he suggests. Which is true but may raise your expectations given that this is a modestly-budgeted British movie.

What he liked about the script, he says, was how different it felt to any other zombie thing he'd seen (or appeared in presumably). "They're all just post-apocalyptic this and that. But this was a stage on from that.

"But it was also about how we treat zombies. And how we treat refugees."

Ah yes. There's a political strand in there if you choose to accept it. I think it's fair to say Scott very much does. He seems drawn to the political theme of late. The aforementioned TV series Full Circle falls squarely into that ballpark. The character he plays is a Democratic Party presidential candidate.

"They all expect him to get elected, but he gets caught with his pants down in a sex scandal. So it's really about the political shame that envelops him. It examines politics the dirtiness of politics. Obviously very current." He doesn't say the word Trump but …

Even in our short time together the dirtiness of politics is something he circles around to more than once. Earlier this year he opened an exhibition Sacrifice at the Somme in the Gordon Highlanders Museum in Aberdeen. His grandfather had served in the regiment during the First World War. He wonders if we've learnt anything as a species from that conflict. He fears not.

"I think since the establishment of the European Union there hasn't been a war in Europe but there have been wars everywhere else perpetrated by us and America. And I think we're in a perpetual state of war because it's good for the economy. And it's dressed up as freedom fighting in the name of democracy.

"It's a f****** lie. The hypocrisy of the West in the way they approach the Middle East, Afghanistan, Iraq. We know all about Tony Blair and George Bush. But even with Obama and his drone programme kids are getting murdered. Children are being blown to smithereens by cluster bombs. The reality is messy and it's not anything to be proud of."

He cites Syria and the refugee crisis too. "Listen, you always try to find the good in people. And I think there are a lot of good people. Liberals see America as being the bad guys but there are great journalists, great politicians, great lobbyists who have done their utmost to try to expose the realities of politics, how dirty it is."

Of course he lives in the belly of the beast himself. In Los Angeles to be exact, with his wife the actor Claire Forlani and their family. What does the word Scotland mean to him now? "It's home. It's in my heart. It's my favourite country in the world. I feel very, very comfortable when I come home."

And does that Scottishness manifest itself in LA? "I'm a Scotsman wherever I go."

Yes, but does that mean he's running around to the local 7-11 of an evening looking for a hit of Irn Bru?

"No," he laughs. "That doesn't make me Scottish."

In short, Dougray Scott will clearly not be showing any middle-aged spread off any time soon. Quite frankly, he's making the rest of us look bad.

The Rezort is available on VOD from today (October 17).