Lily Collins will star as Polly in a live-action Polly Pocket movie being developed at El Segundo-based Mattel Studios.

Mattel announced the project Wednesday, Sept. 16, alongside producing partners Reese Witherspoon's Hello Sunshine and Amazon MGM Studios. Collins, a two-time Golden Globe nominee known for Emily in Paris, will also produce through her banner Case Study Films.

Jordan Weiss, whose credits include Freakier Friday and Sweethearts, and Dan Brier, who co-wrote Sweethearts, are writing the script. The film draws on Mattel's micro-doll line. The brand debuted in 1989 and was relaunched in 2018.

Robbie Brenner, president and chief content officer of Mattel Studios, is producing for Mattel. Witherspoon and Lauren Neustadter are producing for Hello Sunshine, with Emily Ferenbach as executive producer. Mattel Studios executives Darian Greenbaum and Ivan Sanchez are overseeing the project.

The deal is the latest from Mattel's growing entertainment arm. The company formed Mattel Studios in June 2025, combining its film and television units under Brenner. She reports to Mattel Chairman and CEO Ynon Kreiz. Brenner is a two-time Academy Award nominee for Best Picture for Barbie and Dallas Buyers Club.

When the studio launched in June 2025, Kreiz said the vision was "to collaborate with leading creators to make standout quality content based on Mattel's iconic brands that will resonate in culture and appeal to global audiences."

Mattel Studios already has two films in the pipeline. Masters of the Universe, starring Nicholas Galitzine, premiered in theaters June 5. Matchbox, an Apple Original Film directed by Sam Hargrave, is set for an Oct. 9 premiere on Apple TV, according to Vital Thrills.

The Polly Pocket project also follows Mattel's global Bluey licensing deal, which the company announced Sept. 17.

The film is in early development. A script is being written, but no production start date or release window has been set.