Behind the Scenes With Jared Leto, 'Free Solo's' Alex Honnold and Co-Director Jimmy Chin at a Climbing Gym in L.A.

Leto joined Oscar-nominated co-director Chin of climbing documentary 'Free Solo,' along with the film's subject, for a day of climbing.

"Jared loves climbing," Free Solo co-director Jimmy Chin told The Hollywood Reporter of Oscar-winning actor Jared Leto (Dallas Buyers Club). "We all love climbing, so it's pretty easy."

Leto and pro climber Alex Honnold, whose historic free solo climb of Yosemite National Park's famed El Capitan wall is the subject of Free Solo, have struck up a friendship and climb together regularly. The group was joined by The Hollywood Reporter for a day of climbing at the Sender One gym in Los Angeles.

Chin, who is married to his Free Solo co-director Elizabeth Chai Vasarhelyi (the husband and wife directing team met during the making of Meru, the documentary which also put their work on the map), demonstrated some technical terms heard in the film such as "jug up."

"Once you've rigged the ropes and you get up there, you have to coil them up and sling them off of your harness," Chin said as he explained a technique he uses to get a shot while climbing. "It's actually a pretty good simulation of what we're doing on El Cap when we were shooting with Alex."

Chin shot the photos for THR's story during the climb, which left Leto winded, saying, "Who knew that modeling and rock climbing together were this brutal sport?"

"Imagine doing that stuff on El Cap, just hanging, taking pictures," Honnold replied.

Free Solo, starring Honnold and directed by Vasarhelyi and Chin, is nominated for best feature documentary at this year's Academy Awards. It recently won the BAFTA for best documentary.