Suranne Jones suffered whiplash and bruising while filming her own stunts for new crime drama Vigil – set aboard a submarine.
She admitted she spent her evenings soaking in the bath after shooting.
Jones told The Scottish Sun: "When I first read the script, I was like, ‘Oh my god, this sounds amazing – I get to do all these stunts!’ But I forgot how old I was.
"I thought I was 23 when I was reading it, and that’s not true any more. So I had to do a lot of working out just to build up my strength in order to do those scenes.
“I got whiplash, I put my back out a couple of times and I was covered in bruises. Every time I went home, my husband was like, ‘What the hell have they done to you now?’
“It was fun to do... but I was hobbling home and having Epsom salt baths during filming.”
And the Gentleman Jack actor and former Coronation Street star admitting filming in cramped conditions to replicate the interior of a submarine was not easy.
Watch: The trailer for new BBC crime drama Vigil
She said: "It was claustrophobic. There’s a great scene where Amy tries to get in her bunk.
“I’m quite tall and not of small build, and the director was like, ‘Can you get up there a little more gracefully?’ But I just couldn’t do it, because they’re so small.”
Vigil also stars Game Of Thrones actor Rose Leslie as Jones's police colleague and lover, and follows their complicated relationship as they investigate the death of a naval sailor while working separately, one on land and one on the sea.
Vigil begins on BBC One and iPlayer at 9pm on Sunday 29 August.
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