With production currently under way in Los Angeles on the Entourage movie, actor Billy Bob Thornton has joined the cast in a supporting role. In addition, we also have new story details for this highly-anticipated adaptation.

Adrian Grenier (Vincent Chase), Jeremy Piven (Ari Gold), Jerry Ferrara (Turtle), Kevin Connolly (Eric Murphy) and Kevin Dillon (Johnny "Drama" Chase) all reprise their roles from the HBO hit series Entourage, with the plot centering on Vincent Chase's new big-budget Dracula movie that is going into production. Billy Bob Thornton plays a billionaire cowboy who transitions into the world of film financing, agreeing to put up the money for Dracula. He sends his 20-year-old son to Los Angeles to keep an eye on the project for him, although the son has yet to be cast.

Entourage series creator Doug Ellin is directing from his own screenplay, with Mark Wahlberg, whose real-life Hollywood stories served as the inspiration for the TV series, producing alongside Rob Weiss. The original series ran for seven seasons between 2004 and 2011, which followed Vincent Chase's rise through the Hollywood ranks. The long-awaited movie finally got the green light from Warner Bros. in October, just one month after a report that negotiations with the cast members had hit an impasse, after they reportedly asked for more money to star in the film. We also reported in November that supermodel/actress Kate Upton was being eyed to play Vincent Chase's new love interest, but we haven't heard anything more about her involvement since then.

RELATED: Entourage Movie Review: Just Like the TV Show, But Longer

Billy Bob Thornton most recently starred in the drama Parkland, and he just wrapped production on Warner Bros.' The Judge. He will also be seen later this year in FX's limited series Fargo.