Claire Foy has revealed she battled a ''horrible and debilitating'' tumour in her eye when she was just 17.

The Golden Globe winning-actress has admitted she almost had her dreams of becoming a star dashed before they had really begun after being marred with illnesses throughout her childhood, including a potentially life-threatening tumour in her eye.

But instead of making her shrink away, the 33-year-old star insists her battles only made her more determined to ''grab the life [she] wanted''.

She said: ''It was horrible and debilitating, but it made me realise that I needed to grab the life I wanted. If that hadn't happened, I don't know if I would have been brave enough to throw my cards on the table and say I wanted to study drama.''

Fortunately for 'The Crown' star, the tumour was removed without the need for invasive surgery, and Clair admits she's ''lucky to have a face''.

She added: ''I'm quite lucky to have a face. I was a bit like Cyclops and it was all a bit scary. I was on steroids for about a year and a half afterwards that makes you put on a lot of weight and have really bad skin.''

After her successful battle against her eye tumour, Claire applied to drama school, but admits the experience didn't automatically turn her into a confident actress.

She said: ''I was never the prettiest or the most talented girl. It was always an uphill struggle. I've loved drama, but somehow I just thought everyone else was better than me.''

Even now, the star is still nervous when it comes to certain parts of her job, as she says she loathes filming sex scenes.

Speaking to The Sun newspaper, she said: ''If I never had to do a sex scene again, that would be the best thing in the world, because no one in their right mind would enjoy that.

''You're worried about what the crew are thinking, whether they're really uncomfortable, whether you're uncomfortable. You're just thinking, 'God, let this be over!'''