Marshall Allman, a series regular on HBO’s “True Blood,” has been cast in the family comedy/drama feature “Jayne Mansfield’s Car” with Billy Bob Thornton directing from a script he co-wrote with Tom Epperson.Allman plays the naïve son of Robert Duvall’s character. John Hurt, Kevin Bacon, Robert Patrick, Frances O’Connor and Ray Stevenson also star. “Jayne Mansfield’s Car” began filming in Georgia on Wednesday. Alexander Rodnyansky produces for his AR Films and Geyer Kosinski produces for Media Talent Group. Allman’s next films include “Blue Like Jazz” and “Sugar.” He’s repped by Gersh, 3 Arts, and Karl Austen of Jackoway Tyerman.