LL Cool J is the epitome of, well, cool, according to the NCIS cast, who told Us they can't wait for fans to see the actor's latest cameo on the flagship series. "He comes and he's an assassin. He just comes and gets the job done," Brian Dietzen, who plays medical examiner Dr. Jimmy Palmer, exclusively told Us Weekly at the 2026 CBS Fest on Wednesday, April 15, describing how professional LL Cool J, 58, is on set.