EXCLUSIVE: After making his breakthrough on the Martin Scorsese exec produced HBO series Boardwalk Empire, Jack Huston has been set by Scorsese to join the cast of The Irishman, the fact-based mob epic that Scorsese will direct for Netflix. Scorsese has Robert De Niro, Al Pacino, Joe Pesci, Harvey Keitel, Bobby Cannavale (a memorable killer himself in Boardwalk Empire), and Ray Romano as part of the ensemble. The drama is about Frank “The Irishman” Sheeran, a reputed hitman suspected of involvement in the disappearance and murder of Teamsters leader Jimmy Hoffa. De Niro plays Sheeran. They are keeping Huston’s role under wraps.

Producers of The Irishman are expected to be Fabrica’s Gaston Pavlovich, Jane Rosenthal, Scorsese and Emma Tillinger Koskoff. Also on board: Scorsese’s longtime collaborators Ellen Lewis (casting director) and Thelma Schoonmaker (editor). The film is expected to get a small theatrical release to qualify for Oscar.

This project has been embroiled in controversy when the author of the book I Heard You Paint Houses (which is slang for a hit, ala “painting” the walls with blood), Charles Brandt, penned it based on Sheeran’s deathbed confession. The hit man claimed to tell the real story of the disappearance of former Teamsters boss Hoffa. However, the account Sheeran told to Brandt has been disputed. Still, the FBI actually thought enough of Sheeran’s confession to pull up several floor boards from a house where he said he shot and killed Hoffa to look for DNA evidence. Latter the bureau said that the samples found weren’t from Hoffa.

It’s one of the coldest cases in history, but there is no statute of limitations on murder, so it remains open.

Over the years, many stories about what happened to Hoffa has sprung forth, all to be debunked one by one by one. There are a couple of men still alive whose knowledge of the event would carry weight with the FBI and who the bureau believes really do know what happened on July 30, 1975 after Hoffa got into Chuckie O’Brien’s car outside the Machus Red Fox restaurant and then disappeared. But these guys (now in their 90s) still aren’t talking.

Huston is repped by UTA and Untitled Entertainment.