Michael Sheen has shared that he handed back his OBE three years ago.
The actor made the revelation during an interview with journalist Owen Jones, stating he had made the decision after learning more about the history of Wales and its relationship with Britain.
He undertook the historical research while preparing to give the 2017 Raymond Williams Lecture, named after the Welsh writer.
Sheen, 51, explained: "Raymond Williams famously wrote a piece called Who Speaks for Wales? in 1971 and I took that as the starting point for my Raymond Williams Lecture to do 'Who speaks for Wales now?'. In my research to do that lecture I learnt a lot about Welsh history."
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"By the time I'd written that lecture, and I think I'd been given the OBE a year before, or maybe two years before, I remember sitting there going 'I have a choice, I either don't give this lecture and hold onto my OBE or I give this lecture and I have to give my OBE back'.
"I wanted to still give the lecture so I gave my OBE back," he said.
Sheen added that he meant "absolutely no disrespect" in returning the OBE and that he had felt "incredibly honoured" when being awarded it in the 2009 New Year’s Honours for services to drama, noting it had helped his career both inside and outside of acting.
"I just realised I'd be a hypocrite if I said the things I was going to say in the lecture about the nature of the relationship between Wales and the British state and the history of it," he went on.
Sheen disclosed that while at the time he said he wouldn't publicise it, he would be "transparent" if anyone ever questioned him on the matter and that Jones was the first to do so.
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