How Khris Davis transformed into 'Big George Foreman': Filming stopped for 8 weeks to gain weight

Khris Davis went the distance to fully portray "Big George" Foreman on screen.

Just capturing the boxing icon's physical presence in "Big George Foreman: The Miraculous Story of the Once and Future Heavyweight Champion of the World" (in theaters now) required not only learning to box as Foreman but also embodying his dramatic body changes – including Foreman's 100-pound weight gain before his legendary comeback.

"I wanted to take people on the whole journey. And I kept wondering, how we were going to do this? I didn't want to have different actors for each stage," says writer/director George Tillman. "And then I met Khris Davis. He was 6-foot-4 and had the chops to do it all."

Tillman took the dramatic step of halting filming for eight weeks to allow "Judas and the Black Messiah" star Davis, 37, to gain 45 pounds (and shave his head) to portray Foreman's boxing return at age 38 and his second heavyweight championship win in 1994, at 45.

Here's how it went down for "Big George Foreman":

Khris Davis captured George Foreman's boxing, took the punches

Tillman remembers every move from Foreman's iconic boxing matches such as the shocking 1973 Joe Frazier knockdown of his first championship and the epic 1974 "Rumble in the Jungle" with Muhammad Ali. He wanted to exactly replicate those punches on the canvas.

Davis treated his work with Darrell Foster, who trained Will Smith for 2001's "Ali," as "fight camp."

'Darrell told me that rather than training for a film, we were going to train for a championship fight," says Davis. "I knew people would know (Foreman's) fighting style as right or wrong. They've seen these fights a million times. I had to get the fighting right."

Key moments such as the punch combination Ali delivered to bring Foreman down in the "Rumble" were reconstructed at close range with Davis taking the hits to the face.

"He had to take the punches. We had a code name for that, it's time for 'specials,' " says Tillman. "We did that scene 45 times."

How did Khris Davis gain the weight to play 'Big George' Foreman?

Stepping in at an imposing 220 pounds, Davis is impressive as Foreman in his early boxing years from ages 17 to 30. But he also had to transform into the older Foreman, who gained 100 pounds in retirement before returning to boxing in 1987 at 38.

"I knew I wasn't going to fit in my blue jeans. So I went out and bought a whole bunch of sweatpants two sizes too big and sweatshirts," says Davis. "And I just wore workout clothes."

Under professional guidance, Davis, a pescatarian, consumed 7,000 calories a day to go from 225 pounds to 270 in five weeks.

"I'd have half a side of salmon just for lunch with rice and beans, it was an incredible amount of food," says Davis. "Sometimes my cheeks would be filled to the brim. And I would have to tell myself, 'Just get it down.' Then it would be a 700-calorie protein shake an hour later."

Davis, back down to 230 pounds, says he still finds it "remarkable how big I got. I look at pictures and cannot believe I did that."

The real George Foreman was shocked by the transformation

There would be no bald cap for the final piece of the Foreman transformation. "I had no problem cutting all my hair off," says Davis.

His appearance was so different that the real Foreman looked right past Davis when the actor showed up to shoot the first comeback fight.

"I wish that we would have recorded George's face when he saw me. He was so confused like I was some strange man walking up to hug him," says Davis.

Davis savors the complete metamorphosis.

"I never questioned whether or not I was going to have to gain weight. or shave all my hair off, or show up for every fight and throw every punch in this film," Davis says. "I never questioned the commitment that I was going to put in. That's the only way that I understood how to tell this story."

Take a deep dive into George Foreman's story:

• George Foreman: Boxer sued by a third woman for alleged sexual battery against a minor in 1970s

• George Foreman on Leon Spinks: Trademark smile was late boxing legend's' 'greatest gift'

• Muhammad Ali: 'Rumble in the Jungle' title belt goes to Colts owner Jim Irsay for $6.1M

• Muhammad Ali documentary: From the Rumble in the Jungle to Parkinson's

This article originally appeared on USA TODAY: 'Big George Foreman': How Khris Davis transformed into two-time champ