Hugh Bonneville's general knowledge is set to face their biggest test - on screen in Who Wants To Be A Millionaire?
The actor, better recognised as Downton Abbey's Lord Grantham, will team up with Royal Navy submarine engineer Lieutenant Gary Beels for a special Remembrance edition of the TV quiz to win money for the Forces Benevolent Funds.
"I am absolutely dreading my encounter with the Smiling Tormentor, otherwise known as Chris Tarrant. However, I have every confidence that Lt Beels is a genius," he said.
"I only hope that when he realises I am as thick as two short planks he doesn't make me walk one of them. I'm sure we'll have a lot of fun on the night and hopefully we'll raise some much needed money for The Royal Navy and Royal Marines Charity."
TV presenter Melanie Sykes and The Fast Show's John Thomson will partner Army medic Major Nicola McCullough and RAF hero Sgt Derek 'Dutch' Holland.
"I love Who Wants To Be A Millionaire, even though it's utterly terrifying. I'm only hoping that my partner Nicola is as clever as she is brave. That way, we stand a chance of winning a respectable amount of money for a worthwhile cause," Melanie said.
John described the forthcoming appearance as "a great honour to have been asked and to support our noble, heroic forces."
The Remembrance Special, hosted by Chris Tarrant, will be shown on ITV1 on November 9.