The Crown star Jason Watkins has said it was “very difficult” to film an episode depicting the Aberfan disaster following the death of his daughter eight years ago.

The actor, who plays prime minister Harold Wilson in the lavish Netflix royal drama, and his wife Clara lost their two-year-old daughter Maude in 2011 from sepsis.

One episode in the third series of The Crown includes scenes based on the 1966 Aberfan coal-tip disaster, in which 144 people died, 116 of them children.

Watkins told ITV’s Lorraine: “It’s an incredibly moving film – each episode is a film in itself – and we filmed not far from Aberfan, and the care and attention that was taken by everyone in production…

“And people probably know I lost a child, me and my wife Clara lost our Maude in 2011, so to go and have an episode about the loss of a child was very difficult, and I think I suppose above anyone else wanted to make it in the right way.

“But I think what it does is it helps us to remember what happened. The generations that followed are probably not as aware of that terrible tragedy.”

He said the episode, the third of the 10-part series, “remembers that particular, that terrible tragedy”, and he added: “I’m very proud to be part of that, no matter how difficult it was.”

Watkins, best known for winning a Bafta for playing the lead in The Lost Honour Of Christopher Jefferies and Tim Ifield in Line Of Duty, is new to the cast of The Crown for its third season, along with Olivia Colman, Helena Bonham Carter, Tobias Menzies and Josh O’Connor.

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Jason Watkins as Harold Wilson in The Crown (Sophie Mutevelian/Netflix)

The new series covers the events of 1964-77, and sees Wilson become close friends with the Queen, played by Colman.

Watkins said: “Harold Wilson was a working-class boy, grammar school, did very well, got himself to Oxford and then became prime minister. He was a socialist, very much championing the poor and the underprivileged – his father was made redundant when he was young – I think that stayed with him, so he had a kind of social agenda, perhaps.

“And you’d think that him and the figurehead of the establishment wouldn’t necessarily get on, but they formed a very unlikely friendship which spanned many years, which is touching and is touched upon throughout the series, in the many scenes I have with her.”

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Olivia Colman and Tobias Menzies in The Crown season three (Des Willie/Netflix)

Watkins said he is a “huge fan” of The Crown and believes its appeal is because it is a combination of real events and drama.

“It’s this fantastic mix, the mix between the private and the public, the Queen’s personality and what she has to deal with and how that affects her, and the pomp and dealing with large events, which of course both Harold Wilson as a leader in his respect and she as a leader in hers, where they meet and how they explore the nature of government.”

The third series sees Colman take over the role of the Queen from Claire Foy, while Menzies replaces Matt Smith as the Duke of Edinburgh, and Bonham Carter succeeds Vanessa Kirby as Princess Margaret, while O’Connor stars as Prince Charles.

The Crown series three launches on Netflix on November 17.