Tennis star and women's rights icon Billie Jean King has applauded Emma Stone for keeping her distance as she prepared to play the athlete in Battle Of The Sexes.

The Oscar winner portrays King in the film, which revolves around her famous 1973 exhibition match with Bobby Riggs, and she chose not to hang out with Billie Jean while researching the role.

"She came to the apartment in New York... but I didn’t see her much and she didn't want to see me," King recalls, "but she didn’t tell me that.

"When Holly Hunter played me in a TV movie (When Billie Beat Bobby), she couldn’t get enough of me, but Emma said, 'You’re fully formed, you’re in your 70s, I want to go back when you’re 28, 29 and know that person'.

"So she read, she looked at every video tape and tried to remember me at that age. I think she chose the right process for what she needed in the movie."

The film also features Steve Carell as Riggs.