Michael Sheen plans to abandon his acting career to fight what he calls the rise of the “hard populist right” in Britain and beyond, according to a recent interview to publicise his new film.

The 47-year-old, perhaps best known for playing Tony Blair in the film The Queen, starring Helen Mirren, told The Times he plans to “work less as an actor, and possibly stop ... for the time being”.

“Once I’m in, I’m fully in, and this is big. It will be a big change for how people relate to me,” he said in an interview to promote the new Jennifer Lawrence sci-fi blockbuster, Passengers, in which he plays a robotic barman.

Sheen said he was not signed up for any future acting projects.

Although he has been based in Los Angeles for the past 14 years, home remains the south Wales steel town of Port Talbot, which voted overwhelmingly for Brexit in the June referendum – a result that initially left the actor “sad and frustrated” but then determined to fight back.

He said he wanted to spend more time in Wales, which was characterised by a “romanticism about the past – and then a kind of bleakness about the present, and then just a blank space about the future”.

Donald Trump’s victory in the US presidential election put “massive urgency” into a decision to go home. “How can I be most effective?” Sheen said. “What am I going to do?” as he jabbed himself in the chest.

His political awakening came during research for The Passion, which was performed in April 2011. Guardian theatre critic Lyn Gardner described it as “an epic piece of theatre, experienced in real time and real space over a 72-hour period in different locations across Port Talbot”.

Sheen told the Times: “It started with a connection to something, and an idea of why I wanted to do it. How I was going to do it emerged over time and was a lot to do with listening rather than telling.”

Then, in March 2015, Sheen delivered a passionate defence of the NHS against “bland” politicians, whom he said were in thrall to the market, from both Conservative and Labour parties.

Speaking at a 2015 St David’s Day march to celebrate the NHS and its founder, Aneurin Bevan, he noted the politician’s “burning hatred for the Tory party” and attacked Margaret Thatcher’s infamous claim that there was no such thing as society.

His anger was also aimed at the timidity of Labour politicians and the party’s record in office.

“There is never an excuse to not speak up for what you think is right,” he said in that speech. “You must stand up for what you believe. But first of all, by God, believe in something!”