Reese Witherspoon will mark her documentary debut by producing a feature-length film about legendary tennis player Martina Navratilova.

The Academy Award winner has signed up to produce the movie under her Hello Sunshine banner, with plans to undertake the project alongside Pulitzer Prize-winning journalist Glenn Greenwald and producer Suzanne Gilbert.

The Navratilova documentary will focus on the tennis star's battles off the court as an activist for the rights of women and members of the Lesbian, Gay, Bisexual and Transgender (LGBT) community.

"The issues raised by Martina's legacy resonate now more than ever, which is why it's so important to tell her story to new generations of engaged young people who may not be aware of the vital role she played in shaping expectations around female identity and LGBT equality," Charlotte Koh, head of digital media and programming for Hello Sunshine, who is also on the production team for the documentary, told Variety in a statement.

Navratilova, now 61, is considered one of the most accomplished players in tennis history after winning 18 singles titles, 31 major women's doubles titles and 10 major mixed doubles titles.

"As monumental as Martina's on-court achievements were, they pale in comparison to her role as a pioneer and trailblazer on questions of feminism, women's athletics, equality for gay and lesbians across the planet, transgender visibility, immigrant rights, and the right of political dissent," journalist Greenwald added in a press release. "I'm excited to be partnering with Reese and Hello Sunshine to explore her truly enduring legacy, her remarkable courage directly or indirectly inspiring millions of people who lacked any other role models."

Witherspoon founded Hello Sunshine in 2016 in a bid to bring more inspiring stories about women to the big screen.