Katy O’Brian Says Sydney Sweeney ‘Didn’t Care’ About Getting Hurt During Fight Scenes in Christy Martin Biopic: ‘She Was Like, “If You Break My Nose, That’s Fine”’

Katy O’Brian says it “felt good” getting punched by Sydney Sweeney while filming their boxing matches for the upcoming biopic about boxer Christy Martin.

Sweeney stars in the movie as Martin, who was one of the most well known female boxers of the 1990s. O’Brien plays a fellow boxer.

Sweeney packed on 30 pounds for the role. “My body was completely different,” Sweeney told W magazine earlier this year. “I didn’t fit in any of my clothes. I’m usually a size 23 in jeans, and I was wearing a size 27. My boobs got bigger. And my butt got huge. It was crazy! I was like, ‘Oh my god.’”

She added, “But it was amazing: I was so strong, like crazy strong.”

I caught up with O’Brian Thursday night at the A24 premiere of the new Ari Aster film “Eddington” at the DGA in West Hollywood.

“I got punched quite a few times,” O’Brian said of getting in the ring with Sweeney. “It felt good. It was great. It better read well on camera.”

Even so, she admits that it did “not feel good” to have to hit Sweeney. “Even with the extra 30 pounds I would still have 20 to 30 pounds on her so it never feels good,” O’Brian said. “But she didn’t seem to care very much.”

Sweeney agreed to do her best not to go too far with O’Brian. “I was just like, ‘Please, don’t break my nose.’ I had to do ‘The Running Man’ right after,” O’Brian said. “She was like, ‘If you break my nose, that’s fine.’”

Martin boxed professionally from 1989 to 2012 and became the world champion in the super welterweight division in 2009. In 2010, she survived a murder attempt by her husband, James Martin, who stabbed her multiple times and shot her at their home in Florida. He was convicted of attempted second-degree murder in 2012 and sentenced to 25 years in prison.

Her story was chronicled in the Netflix documentary, “Untold: Deal With the Devil.”

Martin was often on set, O’Brian said: “That alone is intimidating, to have a real person there and then a real person who can kick your butt. That’s all very scary but she was super awesome, really hyped for it and was just a cool positive influence. She’s just a powerful woman and that’s cool to be around.”

David Michod directs the untitled biopic from a script he co-wrote with Mirrah Foulkes.

O’Brian can currently be seen in theaters in “Mission: Impossible – The Final Reckoning.”