Leonardo DiCaprio carried a heavy burden in The Revenant

Leonardo DiCaprio had to work around an incredibly weighty costume when filming The Revenant. Photo / Getty

Actor Leonardo DiCaprio inadvertently got a full body workout while filming The Revenant, as his costume weighed more 45 kilos.

The actor gives a compelling performance as 19th Century frontiersman and fur trapper Hugh Glass, who is left for dead by his comrades after being attacked by a bear.

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Leonardo DiCaprio is Hugh Glass. The Legend who fears nothing.

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Costumes were key to the production, having to convey the drama as well as provide the actors with protection from the winter elements.

DiCaprio's outfit in particular was a labour of love for all involved."It's real and very heavy," costume designer Jacqueline West told Vanity Fair of the bear skin that the 41-year-old actor wears in the movie.

"When it was wet, it weighed over 100 pounds. Leo was carrying that around ... Only someone of his stature could have handled that."

West had to create 20 different versions of his outfit and for the post-bear attack look, she had to painstakingly piece the garments together as his character would have actually done in the wild.

"So much happens to him," she explained, "that it had to really be a philosophical construction and deconstruction, where just like the man, the costume evolves through time."

"[The costume] goes through this evolution where it gets shed and then it re-accumulates until he totally strips and crawls into that horse, and then he's kind of reborn like a baby at birth, bloody and naked."

West found the bear skin at a park department in Canada and believes it plays a key role in the movie.

"The animal that almost kills him is the animal that, in many waves, saves his life," she said.

-AAP