Tiffany Haddish on Fitness Prep to Play Florence Griffith Joyner: 'My Legs Are Going to Be Amazing!'

Florence Griffith Joyner; Tiffany Haddish
Florence Griffith Joyner; Tiffany Haddish

Aaron Rapoport/Corbis/Getty Images; Amy Sussman/KCA2021/Getty Images

Tiffany Haddish has always seen Florence Griffith Joyner as her ultimate #bodygoals idol and is excited to play the late Olympian in an upcoming film about her life.

"This is going to be huge — and my legs are going to be amazing!" Haddish told PEOPLE while promoting her partnership with vitafusion gummy vitamins and the Fruit Tree Project, which plants fruit trees in her longtime Los Angeles neighborhood. "Florence Griffith Joyner was an amazing human being and the more I'm learning about her, the more I'm like 'Wow!' "

The actress and stand-up comedian, 41, lost about 50 lbs. last year, which she says has helped her feel better mentally and physically.

"First of all, it feels good to be able to wear a two piece and not feel like, 'Oh, I got to put a whole sarong on and a very large coverup, coverall situation. It feels good to be able to be free," she says. "And the main thing about the whole transformation is my knees feel like they're happy. And when my legs is happy, Tiffany's happy."

And Haddish says that she's already been sampling a bit of Flo-Jo's signature style, including her daring and unconventional track outfits and her distinctive extra-long fingernails, in preparation for the untitled biopic, which was announced in June.

"Yeah. I have tried on some of the outfits and I must say, I look pretty darn good in them," says Haddish. "I had the long nails over the summer. We don't have long nails right now because there's a lot of typing that I'm doing; I'm in the process of writing my next book. So we need the fingertips so we can move quickly on the keyboard, but the nails will be back sooner than later."

Florence Griffith-Joyner
Florence Griffith-Joyner

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Haddish will also produce the film, which has enlisted Flo-Jo's widower and former coach Al Joyner as a creative consultant. Griffith Joyner famously set multiple records at the 1988 Olympics; she died a decade later at age 38 as the result of an epileptic seizure.

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In November Haddish told PEOPLE her fitness and nutrition transformation during the COVID-19 pandemic quarantine was directly inspired by Griffith Joyner. "I had this thought that I want the body of Flo-Jo," she said then.

"She's so meaningful to me because she is the epitome of what happens when you put in the work, when you treat people well, when you're a good person, wonderful things happen," says Haddish. "I had never seen a woman be beautiful and participating in sports like that — up to that point in my life, anyways. And she changed the game. I feel like she set it up for Venus and Serena [Williams] and all these female athletes that are out here doing big things."