Hilary Swank became ''severely claustrophobic'' whilst filming 'Away'.

The 46-year-old actress starred as astronaut Emma Green in the recently released Netflix series, and has said filming most of her scenes wearing a spacesuit caused her to develop a crippling fear of enclosed spaces.

Hilary had never experienced a phobia of any kind before the show, but was left ''drenched'' in sweat within her costume after going through panic attacks.

In a lengthy Instagram post, she wrote: ''I have never, not once in my life, had a phobia. Until now. And I'm gonna be honest, I never understood them, I always thought 'get over it, it's just a spider, etc. walk away.' Until l, of course myself, became severely claustrophobic. To the point my entire body broke out in sweat and I was drenched within 30 seconds and my face looked like a very ripe tomato...and I almost passed out while trying on my finished spacesuit and helmet for the first time. (sic)''

Since discovering her phobia, Hilary has not been able to ''overcome'' the fear, but has learned how to ''calm her mind'' whilst battling with it.

She added: ''It is not just mental, it is very physical. BUT, our mental minds do control a lot, if not everything. After six months, I was not able to overcome my claustrophobia, but I was able to come to a type of meeting of the minds with it. When we calm our minds and sit with the fear, NOT try and push it away, we can sit with it in a different way, that makes it 'doable'. (sic)''

And the actress hopes sharing her phobia experience will help others feel ''less alone''.

Concluding her post, Hilary wrote: ''Playing an astronaut in AWAY made me push into the sharp edges in a way I never thought it would. This was such an important lesson for me...in so many ways.

''I hope that in sharing this you might feel less alone in whatever it is that takes over your mind and therefore body. Be patient with yourself. #WeAreNeverInThisAlone #Away (sic)''