Reese Witherspoon has called working on new film Wild physically gruelling.
Witherspoon has been at the Toronto International Film Festival to promote Wild, which is based on the true story of Cheryl Strayed.
Witherspoon will play Strayed, who set out on a solo 1,000 mile trek to deal with and get over major events in her life.
Speaking to the Press Association, the actress said: " Physically it was very challenging. I really carried a 60lb backpack through the wilderness.
"We shot the movie over six weeks in Oregon in October, November, it was getting really, really cold.
"So we were walking through freezing cold rivers and hiking up mountains for hours and hours and it was physically really gruelling.
"But so exciting and everybody on the crew was so excited to be part of such a beautiful story."
Wild sees Witherspoon team up with director Jean-Marc Vallee for the first time, as he returns to the director's chair after the success of Dallas Buyers Club.
The movie is based on the memoir by Strayed, and sees Laura Dern and Gaby Hoffmann also on the cast list.
Wild is just one of the projects that we are going to be seeing Witherspoon star in over the next few months, as she has also completed work on The Good Lie, Inherent Vice and Don't Mess With Texas.
Wild is released 16th January.
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