U.S. author John Grisham has sold the film rights to his 1999 legal thriller "Testament."

Previous movies based on his popular courtroom novels include "A Time to Kill," "The Firm," "The Client," "The Pelican Brief" and "Runaway Jury."

Variety.com said producers Mark Johnson and Hunt Lowry are collaborating with 821 Entertainment Group to option the book, while 821's Eric Geadelmann and Ben Horton are expected to serve as executive producers on its anticipated big-screen adaptation.

The novel is about a billionaire's illegitimate daughter, who teams up with a down-and-out attorney to retain the fortune her father left her in his will, against the objections of his grasping kin, the entertainment industry trade newspaper said.

Grisham reportedly will be paid a six-figure sum for the rights to "Testament" and may possibly earn more if the film is made and becomes a success. The scribe will also be allowed to offer his creative input when he deems necessary, which has not always been the case in past adaptations of his work, Variety.com noted.