If you follow him on Twitter you'll be aware that Omid Djalili has been preoccupied with a pretty hefty project recently. The hugely successful comic and actor (and, dare we forget, singer and dancer) is now a high-profile documentary producer too.

We Are Many is a film about the 2003 Stop the War marches - the world's biggest demonstration - the making of which has seen Djalili's team spend a good chunk of the past four years chasing an impressive list of interviewees, from weapons inspector Hans Blix and the late Tony Benn to Damon Albarn and Ken Loach. It got its UK premiere last week [May 2015], and has been 'showered with plaudits', as one news outlet put it.

Our chat had a suitably dramatic build-up too - me making a frantic dash to a Danish hotel room after a flight delay and car problems (Omid was back in London) - but we eventually hooked up, and also discussed the make-up of his stand-up, US TV versus UK TV, Oliver Reed, scary theatre, and his out-in-paperback-soon autobiography, Hopeful. You'd imagine that the making of this film will fill a fair bit of volume two...

'We Are Many' is a serious proposition: how did you get involved with it?

It was being directed by a friend of mine, who went to school with me, Amir Amirani, he'd just got a trailer together. He went on the march, and said 'it'd be interesting to know what happened to all the people, how did that march even start?' I came at it more from... I actually at the time, like a lot of people, was duped into thinking this was a good war and the right thing to do.

It's one of those documentaries where we were very clear: it's a story that tells itself, we really didn't want to be the new Michael Moore, it's just a story about truth. What was the truth about what happened at 9/11, what was the truth about why we went to war, and how did those marches come about? What's the legacy they left? If the people don't want war and we have war, what kind of world are we living in?

That's the basic idea. The film is talking about a second superpower that's emerging, affecting people's decisions: social media has a big voice now. We do have a say. Every tweet, every Facebook post, these things do make a difference. It's been a real labour of love this film, I'm very proud of it, I really hope people go and seen.

Did you find producing interesting?

It is. You're making decisions. You realise when you've been in the business as long as I have, your opinions matter on these things. It's a very collaborative thing, to be part of that collaboration is very exciting, its invigorating, and little decisions can make a big difference. Even who you put in it, what you say before a screening - all these things you collaborate on. I'm just one of those people who likes the collaborative process.

That list of names on the poster is impressive - Tony Benn, Noam Chomsky, Brian Eno - it's like the Intellectual Expendables

The Intellectual Expendables - ha! I like that. Yeah, to give you an idea of the weight of this film, someone like Noam Chomsky, who we interviewed for two hours, he only gets used twice, only because of the sheer weight of what everybody says. It was such a challenge, getting everyone. People like Noam Chomsky, Jesse Jackson, you only see them two or three times. That shows you the sheer weight of what other people are saying.

How difficult was it, actually fitting everything together?

It took a year shaping the final bit, we watched the film a hundred times, just to see if it makes sense. Big bits of it were cut, the film was running to two hours, which was long for a documentary, so we shaved it down to an hour and 40 minutes now - it was all good stuff but it just had to go.

For you personally, was it tough to shift back into comedy mode for your recent tour?

You compartmentalise. People have a lot of different fingers in different pies, and I think it's important to enjoy it, all of us who worked on We Are Many, we really enjoyed it. I don't think there's been a single day where we thought 'ugh, this is a job.'

You've always done different things anyway. Even your stand-up tends to involve song and dance, almost like an old-fashioned entertainer.

Yeah, I think I'm just more entertaining than a lot of comedians. Ha! But I think it's important that an audience doesn't know what's next, it's unpredictable: 'is he gonna sing, is he gonnna dance, is he gonna do stand-up?' - it's good to keep an audience on their feet.

One nice set-piece I saw a few years back involved you doing a medley of songs from various musicals - I can't imagine many other stand-ups doing that...

Yeah, it's just me getting confused, trying to get back to 'Pickpocket' [You've Got To Pick A Pocket Or Two from Oliver] but ending up at The Lion King. The comedy police would say 'oh, he's gone into a singing bit here' - but that was about three years ago and I've watched it back and thought 'oh god.' I've become more of a comedy purist, I watch myself and think 'oh god, where are the jokes, give me more jokes!'

But you've also moved into proper musicals - playing Fagin in Oliver was a huge gig.

It's the sort of thing you couldn't really turn down. Cameron Mackintosh, he was very kind to me, I didn't deserve to be in that musical, but what an experience. What a tremendous five months of my life, and I really, really enjoyed it, and I would do it again, but it has to be the right thing.

You enjoy that intensive theatre thing?

I'm a theatre person, that's my background, I was trained in theatre, I studied it at university. Putting on a play, that's very normal to me. I did [Joe Orton's farce] What the Butler Saw in 2012 which was a wonderful, extraordinary challenge, one of the most difficult plays in the English language. The producer said he was getting a bunch of actor commandos...

It's really funny, no-one pulled it off until we did, and even then out of the 90 shows, 20 of them were stinkers, 20 of them didn't fly. Because the comedic complexity of the structure of the play, if you miss a few beats... we knew from early on, in the first 15, 20 minutes, if those beats weren't set up, that's it, the play's a disaster. It's the difference from weak applause to people taking the roof off, standing ovations.

So it's taught me the fragility of theatre as well, of ensemble work. If I'm off, if I don't set things up then I've messed up Samantha Bond, you know; if Samantha Bond's a bit off, she throws off Tim McInnerny, it's one of those bits where you really have to work as a team. And I found that exhilarating.

Your film CV is incredibly impressive, from Bond films to Shaun The Sheep Movie. What would you say is the highlight?

The high point was having my balls fondled by Oliver Reed in Gladiator. It doesn't get much better than that.

You won an acting award for The Infidel, where you had the starring role - how do you look back on that film?

The Infidel was a tough one because we produced that as well, we got involved in the production side, but that was a tough one. That was the first time I didn't have as much of a voice, but that helped me with We Are Many, when you produce something and think 'my goodness, my instincts are right,' the good things that happen, the bad things that happen.

It was the first time producing and you learn lessons, in this business you learn lessons all the time. You're always growing, always developing, and that's why I'm very lucky to be in this position, because if you learn your lessons the rewards are really wonderful to reap.

You've joked about usually being asked to play Middle Eastern villains - do you get many genuinely offensive stereotypical ones?

Every day, almost every day there's a script that I'm put forward for, and my agent very kindly declines. But you have to take every project for what it is, sometimes it doesn't work out just because of timing. There was an Iranian horror film I was invited to take part in, and I just didn't have time, it was brought to me very late in the day - that would've been interesting.

You've done a lot of TV in the UK and US - which do you prefer?

Oh definitely American TV. Well, it's always a toss-up, having a secondary role on an American TV show or doing The Omid Djalili Show on BBC One; obviously I'd rather do my own show but I love the work ethic for American television, everybody pulls together. If you're looking at - for example - live studio audience sitcoms, which they call 'multi-camera' as opposed to here, the way they pump the audience up, the way they work the room, it's like a proper comedy gig...

Whereas there was one sitcom I did for Channel 4 back in 2000 where the audience had left before we even finished, and we still had scenes to shoot until about 11 o'clock at night - no audience, they just didn't know how to hold an audience!

Obviously things have changed, and that was just my experience. Whereas the Americans, especially on Whoopi [Goldberg's 2003/4 sitcom, that co-starred Djalili], the teams, the warm-up comedians, everything is first class. Even the show I did with Paul Reiser [The Paul Reiser Show], which was sadly cancelled after two episodes, that was a very well run ship, really funny show. It was just up against American Idol.

Have you done many pilots?

Pilots, for American TV? I've done two, and both were picked up, so I've got a 100 per cent strike rate.

Your book Hopeful is out now - why have you only written it now? Did you never fancy it before?

I think it's just when you get older, you'd much rather work at home! I think I was too impatient [before that], I couldn't have sat down long enough to write it, and I wanted to write it myself, I thought that was very important, I didn't want a ghost writer. And I liked it, I found it very therapeutic, it was the right time in my life to look back.

A lot of people were surprised how candid it is.

It's a very honest thing, a very no-holds-barred, a very open and very vulnerable book. I took a lot of time to make it so people can pick up the book and read it, even people who are a bit more cynical. I have ADD, so if I can read it and not get bored then I thought other people could as well.

So far we haven't had a single bad thing said about it, which is very nice. That's the first time I've done anything where there's been universal praise for it. I don't quite know why. Maybe because it's quite well written!

'We Are Many' is available on digital download now and on DVD from 1st August 2016. For more details about the film visit www.wearemany.com