Rousey - judo champ, Olympic medalist and undefeated MMA goddess - is a longtime Stallone fan and self-described "Rocky" girl.
"All fighters love the 'Rocky' movies. It's a common language for us."
Her favorites - the original "Rocky," because "it's just a great movie," and "Rocky IV" (Rocky in Russia) because she lived it, as an amateur rising through the ranks of judo fighters in the mid-2000s.
"When I was doing judo competitions, Americans weren't that popular. That's the situation in 'Rocky IV.' He's the bad guy, the foreigner in someone else's country. And that's the situation I found myself in growing up. I say this a lot but it's true - I've been booed in 30 countries," Rousey said.
She remembers her "Rocky IV" moment," fighting in a semifinal match in Rio in 2007 against a Brazilian crowd favorite. Rousey was losing, in part because she'd dislocated her elbow (perhaps her opponent looked at Rousey's arm and thought, "I must break you"). She was down on points with time running out, boos raining down on her.
"I had to pop my own elbow back in," Rousey recalls. "And I was able to make a move in the last second to win the match. And the crowd erupted in applause. They were just appreciative of a good match."
Here's a good match for you: Rousey and Hollywood. Rousey said she never asked Stallone why he wanted her in "Expendables 3," but he's box office savvy, and knows where the movie business is headed - it's a "Frozen" world, and women now account for a solid majority of ticket purchases. Even action movies need credible female stars (Jennifer Lawrence in "X-Men" movies, Scarlett Johansson in "Captain America: Winter Soldier" or "Lucy") to work financially.
Rousey is at the right place at the right time, with the right mix of charisma and MMA street cred - she doesn't have to sell audiences on her toughness.
Rousey, who kicks the tar out of people all the time, said she found the action requirements of "Expendables 3" pretty routine.
The fancy clothes, on the other hand, were a kick for the notorious tomboy.
"Lizz Wolf is an amazing costume designer, and she was in charge of the whole thing. She took great care of me, because she's been working with these sweaty dudes for so long, she was super-happy to have a girl to dress up. She took me on as her little project."
So Rousey wears a very clingy, very short red dress ("They made it for me!") in a scene that finds her kicking butt in a club. The bit recalls the famous line about Astaire and Rogers - that she did everything he did, in 6-inch heels, and backward.
In other areas, she was fashion forward.
"I braided my hair into an X in the back, as a tribute to X-pendables. And the way the shirts fit around the shoulders, the fingerless gloves, that's all a tribute to the '80s, the sort of glory days of the action movie, with Sylvester and Arnold."
Stallone should take that as a compliment, and what choice does he have? Rousey could probably take him, as easily as she's taken Hollywood. She's already completed "Fast and Furious 7," and the "Entourage" movie.
She's rumored to be defending her MMA title again in December, perhaps against former champ and role model Gina Carano, but she now has one foot in fighting and another in filmmaking.
"I definitely have some very exciting [movies] I'll be doing next year. I'm not at liberty to talk about them. But we're entering an age of female empowerment. What's happening in Hollywood is what's happened in MMA. The reason woman are popular in MMA is because people wanted to watch them. It took a while for people to wake up to that. In Hollywood, there is a similar void, waiting to be filled."
She probably won't have to twist Hollywood's arm.
But she could.