Michael Sheen, star of Good Omens and Masters of Sex, is this weekend preparing for his next, possibly most challenging, role. But his latest production will play out on football pitches in Cardiff, not on TV screens.

The award-winning Welsh actor led a successful bid for Wales to host the 17th Homeless World Cup this year and is now working full time on the staging of the tournament.

“We’re just a fortnight off now and a real momentum is building. I went along to look at the Welsh teams playing yesterday,” he said.

The Homeless World Cup, which will bring 500 players from 50 countries to Wales, will run for a week in Cardiff’s Bute Park from 27 July. With the aim of changing attitudes to homelessness in Cardiff as well as providing fresh employment opportunities, the tournament has invited players from all over the world who have either been homeless or are selling street newspapers, are in recovery from drug or alcohol dependency or are asylum seekers.

Sheen told the Observer he was ready to be criticised for being “a champagne socialist” who campaigns on social issues, as long as he can still make a practical difference.

Facebook Twitter Pinterest The Wales Homeless World Cup team are presented with spare kits and boots by Wales’s women’s football squad. Photograph: Gareth Everett/Huw Evans/REX/Shutterstock

“If I’m scrutinised, then I think that’s right,” he said. “There’s a level of scrutiny you come under as a politician, and luckily I don’t get that. But if someone’s setting out to do what I do, as an activist, scrutiny is actually the right thing. I don’t really mind what people say about me. If people are critical of my motives or call me a champagne socialist or something like that, it doesn’t matter.”

Sheen, from Port Talbot, said he had become “frustrated” with simply signing up to causes as a star name. Three years ago he returned to Wales from his former home in America to try to make a practical difference.

If you want to give money to someone else, what I’d suggest is you also talk to them. It might even be more beneficial

“I now split my time between Wales, in London and in America, as I was dissatisfied. I felt I was a bit of a sham,” he said. “Although it does help to a degree to have an actor’s name attached to something, I wanted to be more involved.”

Sheen, 50, said homelessness had been “a live issue” in the Welsh capital for a year or so. “You go down the high street and you see people in tents. And there’s been controversy about how the authorities have handled it.” “The difficulties surrounding the rolling out of universal credit and the arrival of the food banks mean it is very much on people’s minds.”

When it comes to the morality of giving money to street beggars and homeless people, the actor argues there is no correct answer. “If you as a private citizen want to give money to someone else, what I’d suggest is you also talk to them. It might even be more beneficial. Not just to walk by. If you decide not to give money because you’re worried they may spend it in a way you don’t think is wise, for whatever reason, then fine. But when you go home, perhaps think about supporting a charity or finding out more about the situation, rather than just blocking it out of your mind.”

Sheen said he sometimes gave money if it was to hand and that he tried to engage with anyone on the street if he could.

He plans to focus his work in Cardiff on more than just helping those already in crisis. Instead, he wants to tackle wider inequalities, putting a greater emphasis on preventative work.

“It’s about getting more support for people at risk. Those who have come out of the army or prison. We should also be going into schools, where you can often spot those who may be on the edge of homelessness, then support them earlier. The point of crisis is not the only place to offer help.”