FANS of “Smallville” will get the shock of their lives tonight when the show marks its 100th episode – by killing off a fan favorite.

In the episode (8 p.m./Ch. 11), Clark (Tom Welling) reveals his secret to Lana, while Jonathan and Lex find out the results of the election.

But the big twist will occur when a car accident claims the life of someone close to Clark.

“Smallville,” now in its fifth season, is one of The WB’s most popular shows and is expected to make the transition to the new CW network in September.