"Book Club" is adding another chapter.

A sequel is in the works for the romantic comedy starring Diane Keaton, Jane Fonda, Candice Bergen, and Mary Steenburgen.

Steenburgen herself revealed the news to Andy Cohen on his SiriusXM show "Radio Andy."

"I guess we’re doing 'Book Club 2,' because the film was incredibly successful,” she said. "It made so much money.”

The first movie earned $91 million worldwide — a smash success considering its $10 million budget.

In "Book Club," four friends read "Fifty Shades of Grey," which inspires them to make changes in their romantic relationships.

The actresses all became real-life friends, so getting the gang back together for a sequel seems as much of a social event as a good movie business decision.

“We’re kind of obsessed with each other, because none of us had ever worked together," Steenburgen explained. "Our stories are so incredible. And I love it because I’m the baby of the group.”