Gavin and Stacey’s Ruth Jones stars as Carry On actress Hattie Jacques in a new BBC4 drama (Weds, January 19) that lifts the lid on her juicy love life…

What was your perception of Hattie Jacques before doing this one-off drama about her unusual marriage to Dad’s Army star John Le Mesurier (Robert Bathurst)?

“When I watched the Carry On films as a child she always epitomised the warm, mother hen or matron character for me, rather than the old battle-axe she’s sometimes described as.”

Where you surprised that she had such a steamy affair with her young driver John Schofield (Aidan Turner)?

“I was surprised in the sense that her public persona was of the funny fat woman, not of a very sexy, passionate woman. It’s a real eye-opener!”

How did she manage to keep her juicy private life secret from the public?

“It was a completely different ball game then. The press and the public didn’t have the same access to people’s private lives as they do today. John Le Mesurier and Hattie had to keep her affair with this younger man secret for quite a long time, as it would have affected the public’s feeling towards her.”

Did you sympathise with her even though she’d made her husband thoroughly miserable?

“I definitely sympathised. You have to with a character you’re playing, and Hattie was in a very difficult position. She still wanted to look after and protect John. The lovely redeeming part of the story is that she and John Le Mesurier somehow remained friends. There’s something beautiful about that. It’s also a terribly sad story because she eventually ended up on her own.”

This is set in the early 1960s around the time of filming Carry On Cabbie. Was that movie part of your research?

“Yes I re-watched it and loved seeing her as a confident woman setting up her own business. You realise what an incredibly interesting face she had and how big and beautiful she really was.”

Do you think this drama will affect how people think about her?

“I suppose so, but I think she comes out of it pretty well. The story is told in such a good way you understand what’s going on. I hope people will enjoy discovering there was another side to her personality, and also understand she wasn’t a person with bad intentions.”