Jason Isaacs is an actor in the first Resident Evil movie. Isaacs narrates the opening sequence of the film, and makes an uncredited cameo in the end as William Birkin. According to the commentrary on the original Resident Evil movie both the producer Jeremy Bolt and director Paul W.S. Anderson expressed concern over whether they'd paid Issacs for any of the narration work he'd done.
Isaacs was allegedly supposed to reprise his role as Birkin for the sequel, Resident Evil: Apocalypse, he left the project for undisclosed reasons. The character created to fill the space was named Sam Isaacs in his honor.