Jason Isaacs is an actor in the first Resident Evil movie. Isaacs narrates the opening sequence of the film, and makes an uncredited cameo at the end as William Birkin.
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.