Claire Foy says her jam-packed schedule led to her being diagnosed with fatigue.

Claire Foy

Claire Foy

The 34-year-old actress - who is best-known for her starring role in 'The Crown' - has revealed she was told she was suffering from fatigue after a particularly intense period in her career.

Claire - who has a three-year-old daughter called Ivy Rose with her estranged husband Stephen Campbell Moore - confessed: "You can keep yourself going for a long time, and that's what I've pretty much been doing since I gave birth. My body has paid the price."

Despite the stresses of parenthood, Claire loves watching her daughter discover new things.

She told Vogue magazine: "It's amazing seeing them discover everything for the first time. She's very like a border collie. She needs to run outside.

"She loves pulling faces. And then everybody goes, 'Oh, another actor in the family?' I don't want people to put that on kids. I mean, when I was a kid I was just told to shut up - it was quite nice."

Meanwhile, Claire recently admitted that her anxiety "exploded" when she became a star.

The Emmy-winning actress - who starred as Queen Elizabeth II in 'The Crown' - has been dealing with anxiety for years, but her situation worsened once she found stardom.

She explained: "When you have anxiety, you have anxiety about - I don't know - crossing the road.

"The thing about it is, it's not related to anything that would seem logical. It's purely about that feeling in the pit of your stomach, and the feeling that you can't, because you're 'this' or you're 'that'. It's my mind working at a thousand beats a second, and running away with a thought."