Ewan McGregor and Naomi Watts lived through it filming at the very same beach resort where "The Impossible" happened eight years ago. The stars play a couple on Christmas vacation with their sons in Thailand in 2004. And the impossible is about to happen. The story is all too real.

EWAN MCGREGOR: our film is based on the true story of a spanish family, the Alvarez Belón family. The most scary bit for me: when the water hit, when I came up and I was on my own.

It's an account of one family's struggle to survive, and find each other in the aftermath of one of the worst disasters in modern history: the Indian Ocean tsunami.

And with real survivor Maria Belón on set, Naomi struggled to get her story right. This is no digital effect. Naomi was drenched and dragged for weeks in 35,000 gallons of raging water!

NAOMI WATTS: There was one moment underwater where there was a technical problem and I ran out of breath, and I couldn't get out of the chair. In fact, the chair kept moving and turned directions and that was very, very scary.

Her son, played by Tom Holland, suffered for his craft too.

TOM HOLLAND: We both went for it like there was no tomorrow. I would come home from a shooting day and be rubbing off the cuts and bruises, and then realize that some of them were actually real.

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