“It started the usual way with a call from my agent, but I was kind of split about it,” the star told Netflix. “Half of me thought, ‘That’s a great idea,’ but the other side of it was, ‘I’m on a hiding to nothing with people’s expectations of that character.’ I already knew it was a really good series, as I’d watched it from the beginning – though I started off as a reluctant viewer.

“I’m not a monarchist, and I thought I would have very little interest in the royal family but my wife Kate and I decided to watch it. We just got hooked. It’s so incredibly well made and beautifully produced, but it was Claire Foy’s performance that pulled me into it, as it was a view of the Queen that I wasn’t aware of.”

He added: “What made me the most nervous is the public’s perception of Philip, and whether I could come anywhere close to it. So I went to meet Peter Morgan to talk it through and he told me something about Prince Philip’s journey during series five, which was really exciting.”

Season 5 will focus on Prince Philip’s close relationship with Penny Knatchbull, played by Natasha McElhone. Knatchbull, Countess Mountbatten of Burma, is the wife of Norton Knatchbull. She was one of the 30 mourners in attendance at his funeral.

The upcoming series features a whole new cast including Elizabeth Debicki as Princess Diana, Lesley Manville as Princess Margaret, Dominic West as Prince Charles and Jonny Lee Miller as John Major.