Steve Coogan has criticised "myopic and self-centred" actors who lack political opinions.
The 48-year-old Philomena and Alan Partridge star said he felt he had a "moral responsibility" to be outspoken.
Steve also said he was "not that interested" in comedy and that there was too much cynicism in today's films.
He told the Radio Times: "What I find intolerable among my peers is people who have no political opinions or think they're not interested in politics - as if they think it's like asking are they interested in horticulture?
"It's myopic and self-centred to only have opinions on things that affect you directly. If you have any magnanimity towards the rest of the world, you should be interested in what is going on, even though it doesn't directly affect you.
"I do it because I feel I have a moral responsibility to speak about things, if I am empowered in some way - especially if others won't."
Steve, who has been involved with the Hacked Off campaign on press reform, added: "I mean, I got into the whole thing about the reform of the press because no-one else was."
The comedian also told the magazine: "My big bugbear with a lot of films is that they're cloaked and collapsing under the weight of their own irony."
He said of Philomena, last year's film about an Irish woman's 50-year search for her son, in which he starred in and for which he penned the screenplay: " I wanted to do something that was authentic, real and sincere because that seemed to be almost the avant-garde choice to say something sincere and not be cynical.
"Cynicism is easy and, although people think it's very clever to be cynical, it is, but ultimately it's unsatisfying.
"What's really bold and what is the toughest choice is to talk about love and hope and optimism, and those are the things that people shy away from because they find it awkward or they don't know how to deal with them."
The actor, who has reunited with Rob Brydon for a follow-up to TV series The Trip, said: "I'm not that interested in comedy - that's the problem. It's a busman's holiday for me and I'd rather watch documentaries than watch comedy.
"I like using comedy in drama and that's what I'm more interested in developing. I still want to do Alan Partridge but the more successful I am in doing drama, the more likely I am to carry on doing Alan - because I feel I've got another string to my bow."
He criticised the use of the word "celebrity" by the press to describe people such as himself "because it trivialises the people involved".
"If you say, I am an actor-writer-producer who has an opinion, it's very different from saying that I am 'a celebrity' who has an opinion. I wouldn't describe Ed Miliband as a celebrity or Harriet Harman - they're well-known because of what they do - and I'm well-known because of what I do," he said.