Jessica Biel is a survival expert.
The 'Total Recall' actress - who is engaged to Justin Timberlake - was taught by her father how to deal with extreme conditions, and knows how to stop hypothermia developing.
She said: ''My father taught me to be a survival expert. I know how to prevent hyperthermia if you fall into a freezing cold river; you get out and immediately take off your clothes.
''The best way to heat up your body is to have skin-on-skin contact with someone. So basically, you're both naked.''
Jessica credits her parents as the closest people too her in her life, mostly because of their ''outdoorsy'' nature.
She added: ''Who have I been closest to in my life? My parents. They are very cool outdoorsy people. Growing up, we always camped as a family in Colorado, where we lived. My dad taught me all this survival stuff, like starting a fire and building a shelter out of trees and branches. We are a very close-knit family.''