Elizabeth Olsen cut back on bathroom breaks during Wind River shoot

Elizabeth Olsen and her co-star Jeremy Renner tried to limit their toilet breaks while shooting the new crime thriller because the set was so isolated.

The actors filmed much of the movie outdoors in the snow-covered Utah wilderness, and while the scenery worked well for the storyline, it proved to be a struggle for the cast and crew, particularly whenever they needed to relieve themselves.

"We got used to it (heavy snow), but it was tough for the crew," Olsen told breakfast show Good Morning America. "There's a lot of people to transport and a lot of equipment to transport, and there's no road, so we're on snowmobiles and snowcats (motorbikes)...

"Then you know, bathroom breaks were long, because you had to... go snowmobile back (to the facilities), and then come back (to set)..."

Wind River stars Olsen as a rookie FBI agent investigating a murder on the Wind River Indian Reservation in Wyoming, where she recruits Renner's U.S. Fish and Wildlife Service agent character to work as a tracker.

It marked the first time the two stars had teamed up on a project outside of the Avengers blockbuster franchise, and Renner admits working with Olsen "in a different way, in a real way" was part of what drew him to the project, which was written and directed by first-time filmmaker Taylor Sheridan.

Having to battle the elements during production showed Renner a different side of Olsen, who he discovered is "super tough".

"Tougher than me, for sure," he shared. "Mental toughness, emotional toughness..."

However, Olsen confesses her onset demeanor is completely different from how she acts in real life, because she is a "very fear-based hypochondriac" - and she wasn't a fan of the snowmobiles they had to take to and from the shoot.

"I like doing that (daring stunts) in a film environment when there's a stunt co-ordinator, and safety rules...," she said, as Renner chipped in, "She wanted a seat belt on a snowmobile! I'm like, 'No, there's no seat belts on this thing!'"

Sharing her safety fears regarding the vehicle, she explained, "What you do is you're hovering with all your might in a squat (on the snowmobile), 'cause you're not sitting on those, you're hovering, and you're just working your thighs, and if your thighs aren't strong, whoop (you'll fly off)!"