Jillian Bell is probably best known for her comedic role in “22 Jump Street,” but she takes a dramatic turn in her new film “Brittany Runs a Marathon.”

Bell says the movie about a woman who uses running to get her life together is one of the few that deals with body issues in a way that is compelling and authentic.

The character is based on the real-life friend of writer-director Paul Downs Colaizzo. She turned her life around and lost 80 pounds when she started running.

Bell herself lost 40 in the making of the film. It debuted at the Sundance Film Festival on Monday.

Lil Rel Howery, from left, Alice Lee, Micah Stock, Jillian Bell, director Paul Downs Colaizzo, Michaela Watkins and Utkarsh Ambudkar pose for a portrait to promote the film
Lil Rel Howery, from left, Alice Lee, Micah Stock, Jillian Bell, director Paul Downs Colaizzo, Michaela Watkins and Utkarsh Ambudkar pose for a portrait to promote the film “Brittany Runs A Marathon” at the Salesforce Music Lodge during the Sundance Film Festival on Sunday, Jan. (Photo by Taylor Jewell/Invision/AP)
Jillian Bell poses for a portrait to promote the film
Jillian Bell poses for a portrait to promote the film “Brittany Runs A Marathon” at the Salesforce Music Lodge during the Sundance Film Festival on Sunday, Jan. (Photo by Taylor Jewell/Invision/AP)
Jillian Bell poses for a portrait to promote the film
Jillian Bell poses for a portrait to promote the film “Brittany Runs A Marathon” at the Salesforce Music Lodge during the Sundance Film Festival on Sunday, Jan. (Photo by Taylor Jewell/Invision/AP)