Sir Patrick Stewart has explained how a Jewish doctor left him stunned by revealing the veteran actor was not circumcised.

The man who played Jean Luc Picard in Star Trek said the discovery had shocked him because he believed he had undergone the procedure as a child.

But the consultation with an unnamed Jewish medic made clear that Sir Patrick, now aged 76, had been mistaken for decades.

In an interview due to be broadcast tonight on BBC1’s The Graham Norton Show, the actor, who also starred in X-Men and on stage in No Man’s Land, explains how the situation unfolded.

He said: “One night with my wife, as you do, we were talking about stuff and I mentioned my circumcision and she said: ‘You’re not circumcised.’

“I said: ‘What do you mean? That’s ridiculous, I should know. All my life my mother has told me it was fashionable at the time.’”

Sir Patrick, who has no Jewish roots, grew up in Mirfield, West Yorkshire, in the 1940s.

He continued: “I happened to be seeing my doctor the next day for a check-up so while he was down there I said: ‘By the way, my wife and I have had a little disagreement. I am circumcised, aren’t I?’

“He took a closer look and said: ‘Not! I am Jewish, and definitely know the difference!’”

Embarrassed, Sir Patrick later told Mr Norton his grandchildren would be watching the programme.

It is not known when the thrice-married actor learnt the truth.

In 2012 Sir Patrick played the role of an eccentric British peer in the Israeli film, Hunting Elephants, in Jerusalem and Tel Aviv. He revealed he had enjoyed visited the country the previous year.