Arnold Schwarzenegger, the governor of California and former Hollywood actor, has endorsed John McCain in the Republican presidential race, describing him as a "great American hero" and an "extraordinary leader".
Schwarzenegger's endorsement gives McCain a huge boost ahead of the "Super Tuesday" multiple election contests next week.
He said Mccain's ability to work with both Republicans and Democrats was the main reason why he endorsed the Arizona senator.
California is the largest prize among the 24 states that hold nominating contests on February 5, accounting for 170 of 1,023 Republican nominating delegates on offer.
McCain, the Republican frontrunner, already leads the polls over Mitt Romney, his closest rival and a former Massachussets governor, in California.
The popular governor of California made the announcement in California alongside McCain, the senator for Arizona, and Rudy Giuliani, the former New York mayor who dropped out of the race on Wednesday and is also backing McCain.
"There are people out there that talk about reaching across the aisle, but he has shown the action, over and over again," Schwarzenegger said.
McCain has been backed by a large number of independent voters, but his strength among traditional conservative Republicans remains under question.
He said on Wednesday he believes he can unite with conservatives over what he says is the threat to the US posed by what he calls Islamic extremism.