(CNN)For Emma Stone, living up to the legacy of the indomitable Billie Jean King in "Battle of the Sexes," about the infamous tennis match of the same name, was a big task to take on.
Emma Stone became 'addicted to strength' filming 'Battle of the Sexes'
Not only was King a female athlete who had a major hand in paving the path for women who came after her in the sports world, but Stone physically had to look the part of a sun-kissed champion tennis player.
"It was the first time that I focused so, so much on the physicality of someone," Stone told CNN. "Playing an athlete, that is how she was able to make change in the world...that was her avenue to this voice that she had. So, that made physicality incredibly important."
Stone said the role called for her to get and look "stronger" -- something she found empowering.
"It was the first time I'd ever felt like, 'Oh my god, I can lift a lot of weight.' And I understand how mentally, that can make you feel so strong," she said. "It can make you feel like, 'If I can throw this thing across the room, what else can I do?' You feel like the Hulk, a little bit."
In fact, she said, her newfound physical power was a little intoxicating.
"It was actually very cool. I did not know that I'd like it as much as I did," she said. "At by end it was like, 'Well, I'm addicted to strength. This is awesome.'"
It all ended up being worth it on screen too, says the real-life King.
"She's so much like me in this," she told CNN. "I mean, she gets my voice, my tempo, she gets my mannerisms. It's pretty scary to see."
Surreal as it was, King felt that she couldn't have picked a better actress to portray one of the most important moments of her life.
"I'm lucky, I got the best one to play me," she said. "I got the top of the heap."
"Battle of the Sexes" is in theaters now.