Former Poirot star David Suchet says he worries about the controversy over casting choices.
There has been debate over actors taking roles away from minority groups, with Bryan Cranston defending playing a wheelchair user in a comedy drama.
Suchet, 72, told the Daily Telegraph: “I’m worried about it. I’ve seen a lot of change in 50 years.
“Multicultural casting took time to adapt to. I had to work on myself to become more open-minded, and stop hanging on to fuddy-duddy traditions.
“Theatre has to evolve… but there’s a danger we’re actually becoming narrower. Art must be free if it’s to express itself – you should serve the writing.
“I’ve just been in a Pinter play (The Collection) where I played a gay character. I’m not gay but it crossed my mind, ‘Will there be objections?’
“I’m very passionate that performers should have the opportunity for their talent to emerge, but to say actors should only play themselves would render character actors redundant.
“If you take this to an extreme conclusion, I couldn’t have played Poirot because I’m not Belgian. If this is the way it’s going, I’ll be out of a job.”
Diversity in the film industry is a hot topic, with straight actor Darren Criss ruling out playing gay characters in future for fear of depriving an LGBT performer of a job.
Last year Scarlett Johansson pulled out of film Rub & Tug following a backlash over her casting as a trans character.
Simon Callow recently dismissed suggestions that able-bodied actors should not be cast as disabled characters.
Suchet was talking after John Malkovich played Poirot in The ABC Murders.
He said: “I don’t feel any rivalry. If there’s a pang, it’s that I miss Poirot personally.”