1 of 4 | Dwayne Johnson attends the premiere of “The Smashing Machine” at the 82nd Venice Film Festival in Italy on Sept. 1. Photo by Rune Hellestad/UPI | License Photo
Oct. 3 (UPI) — As a former wrestler, Dwayne Johnson has made an acting career for himself by playing strong and physically imposing characters on screen.
But transforming into former MMA and UFC fighter Mark Kerr for the new film The Smashing Machine required Johnson to put on an additional 30 pounds of muscle. After a wig and 22 prosthetics, Johnson is nearly unrecognizable in the role as Kerr, a two-time UFC Heavyweight Tournament Champion.
The Smashing Machine, which follows Kerr’s career as well as his personal struggles with addiction, comes to theaters Friday. The film also stars Emily Blunt as Kerr’s wife, Dawn Staples, and is directed by Benny Safdie.
Johnson’s not the only actor to take on the physical transformation required to portray some of history’s most iconic fighters.
Here’s a look at seven other actors who got in shape to play legendary MMA fighters and boxers:
Christy (2025)
Like most actors who take on physical roles, Sydney Sweeney said she trained two or three times each day to play boxer Christy Martin. She also worked with a nutritionist, though her diet was a little unusual for the typical actor.
“There was a lot of Chick-fil-A,” director David Michôd told attendees at the Toronto Film Festival, where Christy premiered in September.
“A lot of Smuckers, a lot of milkshakes, a lot of protein shakes,” Sweeney added. “But it was incredible being able to completely embody such a powerful woman.”
Also starring Ben Foster as Martin’s abusive husband, the film hits theaters Nov. 7.
Sydney Sweeney (L) and Christy Salters Martin attend the premiere of “Christy” during the Toronto International Film Festival at the Princess of Wales Theatre in Canada on September 5. Photo by Chris Chew/UPI
Fire Inside (2024)
Actor Ryan Destiny said she went from barely being able to do one push-up to lighting up the screen as boxer-turned-MMA fighter Claressa Shields in The Fire Inside.
Shields told UPI that a training montage showing Destiny in the ring, running, doing push-ups, crunches and more was all authentically her. She said Destiny sought advice from her on how to cope with soreness after filming the scenes.
“Go and get a massage, ice bath, hot bath, rest, drink some water,” Shields said. “It’s OK to recover. I think a lot of athletes should do more recovery.”
Boxer Claressa Shields (L) and actor Ryan Destiny attend the premiere of “The Fire Inside” at the Directors Guild Theater in Los Angeles on December 4. File Photo by Jim Ruymen/UPI
Bleed for This (2016)
Miles Teller underwent intense dieting and training to drop from 188 pounds and 20% body fat to a leaner 168 pounds and 6% body fat for his performance as boxer Vinny Pazienza in Bleed for This.