Feminism isn't just for women, as Oscar winner Emma Stone points out in an Out interview about her upcoming movie, "Battle of the Sexes."

The film tells the story of the legendary 1973 tennis match between Bobby Riggs and Billie Jean King, who was an advocate for equal pay for male and female players.

Equal pay is also still a challenge in Hollywood, as Stone discusses with King and "Battle of the Sexes" co-star Andrea Riseborough.

"I've needed my male co-stars to take a pay cut so that I may have parity with them," Stone noted. "And that's something they do for me because they feel it's what's right and fair. That's something that's also not discussed, necessarily — that our getting equal pay is going to require people to selflessly say, 'That's what's fair.'"

"If my male co-star, who has a higher quote than me but believes we are equal, takes a pay cut so that I can match him, that changes my quote in the future and changes my life."

King responded that such change can only happen when both men and women work together on equal pay.

"You just gave an example of why men are so vital to these changes," the tennis legend said. "They're usually in the power position, and if they start to change the paradigms, things start to shift."

"Battle of the Sexes" opens in theaters September 22.