The actress said she trained with "an aerialist, an acrobat" to prepare for the film

Felicity Jones is revealing some scary behind-the-scenes details from the making of her new movie, The Aeronauts.

The 36-year-old actress, who is reunited with her former The Theory of Everything costar Eddie Redmayne in the film, told Net-A-Porter for its recent cover story that doing her own stunts in the film did not come easy.

The movie follows wealthy widow Amelia Wren (Jones) and scientist James Glaisher (Redmayne) as they set out to fly a hot air balloon higher than anyone in history — despite the mounting dangers.

To prepare for the role, Jones told the outlet that she trained with “with an aerialist, an acrobat – all very Cirque du Soleil” and she “loved the freedom of it.”

“I loved as much as possible being able to be up in the air,” she continued.

However, when it came time to put her skills to the test on her and Redmayne’s first day of filming, Jones admitted things didn’t go as planned.

The Aeronauts
| Credit: Amazon Studios

“Eddie and me were holding hands and hoping for the best as we hit the ground at an incredible velocity,” she told the outlet, recalling their harrowing hot-air balloon crash.

“My eye missed the metal corner of this wooden chest, by about five centimeters. I was wearing a corset as well, to add insult to injury, and at that moment I thought I might actually have broken my back, as I couldn’t move.”

Eddie Redmayne
Credit: Todd Williamson/JanuaryImages/Shutterstock

Despite the balloon-flying challenges, producer Todd Lieberman shared in August 2018 that it was important for the actors to perform their own stunts.

“A top priority for us on The Aeronauts is authenticity. With that in mind, we intend to do as much balloon filming in the sky as the weather will allow,” said Lieberman.

He added: “We’re fortunate that Felicity and Eddie have the nerve to do these stunts themselves as it authenticates our entire approach.”

The Aeronauts hits theaters Dec. 20.