Working class children will be denied the chance of becoming professional actors unless they can study drama at school, actor Michael Sheen has warned.
Sheen, who famously played Tony Blair in The Queen, warned that the path into acting was being closed for many young people from working class backgrounds.
Amid criticism that the profession is increasingly dominated by people who were educated at public school, he called for greater support for drama in the state school system and for youth theatre.
"If you want more working class actors you have to support education. There has to be a drama department in schools," he said.
"If there's not, you can forget everything else after that. Nothing else matters. You haven't got working class actors suddenly deciding to become actors and suddenly being good at it at 30.
"Acting is a craft. You just don't suddenly do it. You can't do it on your own in your bedroom either. It takes ages before you are really good at it.
"So you have got to support youth drama groups but also you have got to force youth drama groups to go out and outreach."
Sheen was speaking at an event at the Houses of Parliament highlighting the latest research by the Sutton Trust showing the UK's "professional elite" is still disproportionately educated at private schools and at Oxbridge.
While he had attended drama classes at his comprehensive school in Port Talbot, South Wales, before joining a youth theatre and then going on to receive a grant to attend drama school, he said those opportunities no longer existed for many young people.
He said that failure to ensure working class voices were heard in the theatre, in film and on television would have a wider impact on the whole culture.
"Part of what changed our culture in the late 50s and into the 60s is that we stopped doing Noel Coward and Terence Rattigan plays and John Osborne came along and wrote something, and suddenly were heard Albert Finney and Tom Courtney - people who voices and accents had never been heard apart from 'All right guv'nor' in the background," he said.
"That's what changed our country and our culture. If we only hear certain stories and certain voices we all lose out."
He added: "As brilliant as I think Benedict is, I don't particularly want to see Benedict Cumberbatch playing a kid from Port Talbot because that's just not his real life."