Harry Potter and The Singing Detective star Michael Gambon stars in ITV’s new, one-off, feature-length drama Churchill’s Secret. Speaking to What’s on TV on the film set last year, the legendary actor said, viewers are in for an eye-opening treat…

“Not many people know Winston Churchill had a couple of strokes and was seriously knocked out! I didn’t know before filming.

“You’re going to see something in Churchill’s Secrets that you probably didn’t know about him.”

Britain’s celebrated Prime Minister is remembered for countless achievements, not least guiding the UK to victory in World War Two. But one thing he was never celebrated for was a healthy lifestyle.

Famous for his love of cigars, booze and late nights, later in his career Churchill suffered a series of health setbacks, which were largely kept hidden from the world. And in June 1953 he had a series of strokes that nearly killed him…

Michael was somewhat daunted at the thought of taking on the role: “When I heard Churchill, I thought ‘I won’t be able to play him!’ But I trusted the director, so I said ‘okay!’

“I didn’t want to do an impersonation, but I did try to sound like him – I don’t know with any success or not. I also had to have my hair cut, I usually have hair down to my shoulders.”

Churchill’s Secret explores the impact of this period of illness on the famous politician, his family, and the political landscape at the time. Told from the viewpoint of Churchill’s fictional nurse, Millie (Romola Garai), the drama shows how Chruchill’s political friends and foes plot a replacement for him, as he fights for his life. And family tensions rise to the surface too, when Churchill’s grown-up children (played by Tara Fitzgerald, Matthew Macfayden, Daisy Lewis and Rachael Stirling) are recalled to be with their stricken father.

With Churchill, 78, at death’s door, his condition was kept secret from the press and parliament as his wife, Clementine (Lindsay Duncan), moved him home…

Michael, 75, said: “Churchill had his flaws. He probably wasn’t a perfect father, and he and Clemmie had their ups and downs, but their long marriage spanned two World Wars.

“I think Churchill must have had an overwhelming desire to get well, and he did it though willpower.”

Churchill’s Secret is on ITV, Sunday 28 February at 8.00pm.