The last episode of the HBO programme ended with Tony Soprano (James Gandolfini) dining with his family as the screen fades to black.
Imperioli, who played Christopher Moltisanti in the show, said he believes that the final scene depicts Tony's death.
He said: "I think he's dead. That's what happens when it goes black, right?"
Last week, Sopranos actor Lillo Brancato Jr. was sentenced to ten years in prison after a botched armed robbery he was involved in resulted in the death of a police officer.