[SPOILER ALERT: If you don’t want to know anything about the new season of 24, scroll down past this item. Seriously. We’re not kidding.]

Some advice for those of you counting down the hours till Jack Bauer’s next harrowing day: The season 5 premiere of 24 (Jan. 15 on Fox) is so shocking, so stressful, that ”people should take a Valium or something.”

That’s what Mary Lynn Rajskub (systems analyst Chloe) told Entertainment Weekly’s Dan Snierson in our upcoming cover story about the show (on stands this Friday, Jan. 6). Echoes exec producer Howard Gordon: ”It’ll scramble everyone’s eggs. Whereas in the past we’ve had this slow-mounting tension, this year starts out with a bang and doesn’t let up. Just when Jack thought he’d lost everything, he finds out there’s something more to lose.”

Once you catch your breath, you’ll have to become familiar with a few new characters (including one played by Sean Astin!). Here’s what Snierson teased about each of them:

First Lady Martha Logan (Jean Smart) Yes, she’s a mentally unstable drama queen — but her hubby should listen to what she has to say.

Lynn McGill (Sean Astin) He’s a young buck from a higher agency who’s brought in to head up operations at CTU. But is he in over his head?

Diane Huxley (Connie Britton) She and her teenage son Derek (Brady Corbet) have been providing shelter for Jack while he’s been hiding out. Of course, they don’t know he’s hiding out. And they think his name is Frank.

Vladamir Bierko (Julian Sands) This rebel Russian billionaire is spearheading an insidious terrorist plot that’s timed to foil the signing of a U.S.-Russia anti-terrorism treaty.

Spenser Wolff (Jonah Lotan) He’s the new CTU systems analyst who pursues a relationship with nutty Chloe. Is he missing a logic chip? And is Edgar jealous?

Christopher Henderson (Peter Weller) The former CTU agent who recruited Jack years ago may be the key to bringing down the terrorists. But his reunion with Jack isn’t pleasant.

So, PopWatchers — biting your nails yet?

addCredit(“Julian Sands: Jean-Paul Aussenard/; Peter Weller: Albert L. Ortega/”)