The 36-year-old actress, who plays Lady Agnes in the drama series, said that she wants to look her best for the show but her husband and Pride and Prejudice actor Matthew Macfadyen doesn't like her looking too toned.
Hawes told The Telegraph: "I asked him if I should go to the gym and he said, 'Everyone could be a little bit more toned'. I thought, 'Thank you very much!' I expected him to say, 'Of course not, my darling, you look perfect the way you are'."
However, she revealed that Macfadyen soon changed his mind, saying: "I did go to the gym for two weeks, but then Matthew said I had to stop as I was looking too muscly."
Hawes recently revealed that she has always loved costume dramas, saying: "They've always been in my life. And obviously I'm married to Matthew. One or the other of us is always doing something in a bonnet. Well, not Matthew! That's behind closed doors."
The couple have two children together called Maggie and Ralph.
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