Called Margot vs Lily, the eight-episode series will air on Nike Women's YouTube channel weekly from the beginning of February, with Nike+ members given early access to the shows.
According to the trailer, the series will follow Lily, a (fictional) fitness-obsessed YouTube celebrity, and her "exercise allergic" (yet strangely slender and glowing) sister, Margot.
In one oddly bitchy exchange, YouTube Lily dares her sister to start her own fitness challenge. Margot, somewhat unkindly, challenges Lily to "get more than zero friends".
Hilarity ensues as Lily is seen rejected by other runners, for dinner and by a book club. Margot, meanwhile, strains her way through various on-camera workouts.
The new series ties in with Nike's wider 'Better for it' campaign, which now has its own hub where women can buy outfits worn by Margot and Lily during the series. The 'Better for it' campaign has been running since April last year, and is part of Nike's effort to turn women's apparel into an $11bn business in the next five years.
A Nike spokeswoman said: "Nike motivates and inspires women to be 'Better For It' with the most innovative digital and physical experiences, and conversations with these consumers made it clear that connecting with them through original programming made sense for their lives.
"Margot vs Lily – A Better For It Production was the result of countless consumer conversations and a desire to surprise and inspire them in a totally new way, ultimately igniting their own Better For It journeys."
Nike has collaborated with filmmaker Alfonso Gomez-Rejon, author Jesse Andrews and director Tricia Brock for the series, which runs until March. Lily is played by Samantha Marie Ware, and Margot by Brigette Lundy-Paine.