Another Kennedy has plunged into politics.

A Kennedy son-law, that is.

A chap called Arnold Schwarzenegger.

For almost a year, rumours have swirled that the star of Terminator 3 would enter the California governor's race.

He confirmed last night that he was in the fray on Jay Leno's Tonight Show.

'It was a very difficult decision to make, one of the most difficult decisions I have made in my entire life,' the 56-year-old Republican -- who is married to John F Kennedy's niece Maria Shriver -- told Leno.

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The Austrian-born star said California Governor Gray Davis, a Democrat, had let the state's people down by allowing the economy to deteriorate to a 'disastrous' level.

Schwarzenegger added his wife, a Democrat, helped change his mind about not entering the race.

The decision puts Schwarzenegger on the path to becoming the second movie star to vie for California's top job, after Ronald Reagan, who was twice governor in the 1960s.