Ellen Gray | Jennifer Aniston steals the show on 'Dirt'

DIRT. 10 tonight, FX.

FRIENDS DON'T let friends be upstaged.

But that's just what happens tonight when Jennifer Aniston pops up in the season finale of FX's "Dirt."

Word of Aniston's guest shot - and the accompanying girl-on-girl kiss - was out so long ago that you might think you'd already missed it.

If the plan was to boost ratings for Courteney Cox's seamy little soap by dragging in one of her "Friends" co-stars, waiting until the end of the season to do it would kind of defeat the purpose, wouldn't it?

So maybe it's true that the off-camera buddies just thought it would be fun.

Too bad that Aniston's the only one who seems to be enjoying herself.

As Tina Harrod, a rival editor who may be out to unseat Dirt Now's Lucy Spiller (Cox), Aniston is utterly believable as a pseudo-sympathetic extrovert who hides her own naked ambition behind a wallet-full of baby pictures.

Even more than Cox, she brings subtext to the world of supermarket tabloids and intrusive paparazzi. So much so that when she was offering tea and sympathy to a sitcom actress who's fallen on hard times, I couldn't help wondering if this was the way Vanity Fair's Leslie Bennetts looked to Aniston during the interview for that September 2005 cover story in which the recently divorced actress reportedly burst into tears before baring her soul.

Tina may be three kinds of slimy, but her catch-more-flies-with-honey approach seems more likely to work than Lucy's I-have-the-video-in-my-vault technique.

But then very little about Lucy works, starting with her face, which barely moves. Cox plays the ruthless editor as a Morticia lookalike with a sad, sad past - suicidal dad, unfeeling mom, ambivalent brother - and perhaps that's what she and "Dirt" creator Matthew Carnahan think it takes to make someone behave the way Lucy does.

Because apparently money - and the fun of being good at something - couldn't possibly be enough.

Earlier in the season, Paul Reubens guest-starred as Lucy's go-to investigative reporter, a once-respectable journalist who'd fallen into a bottle but hadn't lost any of his chops. Or his sense of humor.

I might watch a show about that guy.

But until Lucy lightens up a bit - and don't expect it to happen in tonight's cliff-hanger - I don't see much to dig about "Dirt."

Maybe the 5.3 million or so viewers who tuned in for Fox's "The Wedding Bells" last week can't compete with the audience for "American Idol" or even "24," but that doesn't mean someone at the network shouldn't be paying attention to what they're throwing on the air.

Maybe the 5.3 million or so viewers who tuned in for Fox's "The Wedding Bells" last week can't compete with the audience for "American Idol" or even "24," but that doesn't mean someone at the network shouldn't be paying attention to what they're throwing on the air.

Friday's episode, originally scheduled to be the David E. Kelley show's second, had been postponed the week before, and the third episode aired in its place.

Which means that things that had been already in place in week 2 - like the addition of a new owner for the Wedding Palace and a romantic breakup - didn't occur until a week later.

It's bad enough when serialized shows get rerun out of order, but "The Wedding Bells" was new this month.

For viewers, it's as if Sanjaya were, by some miracle, voted off "Idol," only to reappear the following week, acting as if it had never happened, and insisting on singing.

OK, maybe nothing could be that bad. *

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