Picture: courtesy of IMDb.

Sir Michael Gambon has announced his retirement from theatre, after 50 years of treading the boards.

The 74 year old has decided to quit stage acting after he admitted to suffering memory loss that meant he could no longer remember his lines.

Sir Gambon said: “There was a girl in the wings and I had a plug in my ear so she could read my lines. And after about an hour I thought, ‘This can’t work.’

“You know, when you’re there in front of an audience, that you’re not as good as you could be.

“It’s a horrible thing to admit, but I can’t do it. It breaks my heart. When the script is in front of me and it takes me forever to learn, it’s frightening.”

The memory problems started in 2009, when he was rushed to Accident and Emergency after forgetting his lines caused him to have panic attacks.

Sir Gambon made his theatrical debut in 1962, in Dublin, with a performance of Othello, and has since won three Laurence Olivier Awards.

But speaking to The Sunday Times, the veteran revealed the decision to pull the curtain down on his career.

He will, however, continue screen acting.

He is currently starring in Sky Atlantic’s Fortitude, to critical acclaim, and is due to star in an upcoming remake of Dad’s Army, as Private Godfrey.