Michael Sheen is putting his acting career on hold to focus on political activism against right wing populism, the Masters of Sex star has said in an interview published today in the U.K.’s The Times Magazine.

Sheen credits his involvement with The Passion, a 72-hour “theatrical happening” staged by the National Theatre of Wales in his home town of Port Talbot, as first connecting him with community organizations. He says he now plans to move back to Port Talbot to begin work on grassroots organizing, having already looked at examples in Wales, the Midlands and Spain’s Basque country that could be adapted in Port Talbot.

Sheen also cited Brexit and the election of Donald Trump specifically for his decision, telling The Times that it had given him a sense of “massive urgency.” He has already been publicly politically active in recent years, and notably gave a speech in 2015 defending free health care. The response to that speech, he says, made him “quite scared… that people could feel that I could do something.”

Sheen hasn’t clarified for how long he’ll be putting his career on the back burner, but implies it is indefinite. “It will be a big change for how people relate to me. Once I’m in, I’m fully in, and this is big,” he said, adding that he expects a backlash. “As soon as you start to be effective, then people try to crush you, because it’s dangerous.”

“In the same way as the Nazis had to be stopped in Germany in the Thirties, this thing that is on the rise has to be stopped.”

Sheen is currently seen onscreen in Passengers. His television series Masters of Sex ended its run in November.