Helena Bonham Carter has left production on Terminator: Salvation stalled after members of her family died in a car crash.  Bonham plays Serena, "the lead villain."

The actor’s relatives were on a South African safari holiday on Wednesday when the minibus they were travelling in spun out of control and flipped after a tyre burst.
Helena’s cousin, Fiona Bonham Carter, 51, escaped with a broken shoulder. But Fiona’s son Marcus Egerton-Warburton, 14; mother Brenda, 74; stepfather Francis Kirkwood, 75; and sister-in-law Kay Boardman, 54, all died.
The actor was given indefinite leave from the set in Mexico. [New Mexico, actually - Ed.]
"Everyone here was in a state of shock when the news came through," a source said. [News.com.au]

Well jeez, that sucks.  Not to make light of a tragedy, but if I die in Africa I would at least hope rhinos are involved.