Chrismukkah is about to sweep the nation! Well, at least in "The O.C." it is, and as "Extra" found out, the made-up holiday is just one of two things from the hit show that's creating quite a controversy.

"Chrismukkah takes two holidays and helps blend them into one," "The O.C" creator Josh Schwartz explained. "Two for one, who could turn that down?"

Schwartz came up with the Christmas-meets-Hanukkah concept, and he's even created a line of Chrismukkah gear, including wrapping paper, cards and yarmuclaus (Santa-themed yarmulkes), that will make its debut on tonight's show.

And the holiday is so beautiful in fact, that some guy in Montana has started his own Chrismukkah line. "It's in good fun, but the guy is cashing in on something that we created on 'The O.C.,'" Schwartz commented.

But there's an even bigger controversy brewing on the set of the hit FOX show, and only we've got the scoop! Just when you thought things couldn't get hotter on the set between Seth and Summer and Ryan and Marissa, there's going to be a new couple turning up the heat a few notches.

"Marissa finds herself in a new relationship with someone she never expected," Schwartz revealed. "It's a girl, played by Olivia Wilde -- Alex!"

Yes, Mischa Barton's character will steal Seth's girlfriend. Now that's a love triangle you won't want to miss.

And don't miss your chance to get into the holiday spirit, "O.C." style: click here to get your own Chrismukkah items.