In the thread about The Imaginarium of Dr. Parnassus, there was some discussion about the changes that had to be made after Heath Ledger’s death. As most know, Johnny Depp, Jude Law, and Colin Ferrell took over portions of the role, and due to the surreal nature of the movie the character’s changes in appearance could be explained away.
A couple of other famous examples:
In 1982, Vic Morrow was killed by a crashing helicopter during the making of Twilight Zone: The Movie. Filming of his segment was almost complete, and only a few minor tweaks were needed to edit the story around the missing scene.
Marilyn Monroe died in 1962 while filming Something’s Got to Give. The movie was already over-budget and behind schedule, mostly due to Monroe’s erratic behavior; the project was scrapped and the film was never released.
What other films suffered the death of an actor, and how did it affect the final product?
Brandon Lee was killed during the filming of The Crow during a mistake with staged shooting that ended up being fatal for him. The movie went on to do fairly well critically and commercially.
Oliver Reed died midway through Gladiator (they added his death scene and contrived a bit of CG jiggery to shore in the gaps)
Brandon Lee died on the set of The Crow and similar smoke & mirrors tried to hide this in the unfilmed portions.
Bela Lugosi died near the beginning of Plan 9 from Outer Space so a guy with a cape obscuring his face (Ed Wood’s chiropactor) subbed for the remainder of the shoot.
Jean Harlow died in 1937 after about 90% of her role in Saratoga was completed. They shot her remaining scenes with a double for both her and for her voice. The movie did well, as people went to see her last performance.
Jean Harlow died just before Saratoga was finished; she was rewritten out of a few scenes; others were filmed with a double in long shots or from behind.
Marty Feldman died during the shooting of Yellowbeard. IIRC, they shot a new scene in which his character died suddenly (probably filmed, in part, using a double).
James Dean’s lines in Giant in the final banquet hall had to be read by another actor in post production. It’s Dean’s picture but either Dennis Hopper or Nick Adams said the words. That’s best regarded as hearsay, as I can’t come up with a cite that’s foolproof.
Natalie Wood died near the end of filming Brainstorm, right before the final scene was to be shot, so after the uncompleted film sat around for a couple years, they made an ending using doubles (onscreen and voice).
The Crow is definitely the creepiest of them all, considering the plot is about a murdered (shot, stabbed) rock star that returns from the dead to avenge his murder, and in real life, the actor portraying the undead rock star gets shot making the movie and dies.
Bruce Lee died having shot only 30 minutes of footage for “Game of Death.” They used a bunch of stand-ins and, according to IMDB, even a cardboard cutout and stills to complete the film, which was released about five years after his death.