Must-not-see TV?

For nearly three decades, NBC's Thursday-night comedy block has lived up to its "must-see" billing. Half of the shows that have captured the Emmy for best comedy since 1983 have come from its ranks, including "Cheers," "The Cosby Show," "Friends," "Seinfeld" and, most recently, "30 Rock" and "The Office."

But for all its efforts, the network has rarely been able to assemble four great programs at the same time, subjecting us die-hard regulars to mediocre fare that looks downright dim compared with its solid-gold partners. The latest clunker is "Kath & Kim," a remake of an Australian hit about a dysfunctional mother-daughter team who are supposed to remind you of Laverne and Shirley. Instead, you'll wind up pining for the intellectual banter of Lenny and Squiggy.

It's not the season's worst new comedy -- that dubious honor goes to Fox's "Do Not Disturb," which was mercifully canceled after just a couple of painful weeks -- but it's uncomfortably close.

Kath (Molly Shannon) is a single mother whose profession must have something to do with having a toned body because she works out more than Jack LaLanne. Her regimen is interrupted by the arrival of daughter Kim (Selma Blair), a newlywed who comes pouting home, whining that her new mate won't treat her like a trophy wife.

"We can't go to Applebee's every single night," her hubby says. "We're not millionaires!"

If the two women are uncomfortable with becoming roommates again, it doesn't show. Their visits to the mall are treated as bonding (and boring) adventures. The two episodes provided in advance to critics end with the two of them lounging on patio chairs, gossiping about TMZ, Britney Spears and anything else the writers imagine are popular topics among trailer trash.

There's nothing wrong with women doing their own version of "Dumb & Dumber." Julia-Louis Dreyfus and Wanda Sykes are currently doing an excellent job of it on "The New Adventures of Old Christine." But Shannon and Blair don't seem to be aware that they're doing a silly sitcom.

Blair's favorite approach to comedy over the years has been to put on a sullen face and mumble her way from punch line to punch line. In this effort, she accessorizes that bit with a wardrobe of Daisy Duke hand-me-downs. It doesn't help. She still looks as bored as most viewers will be.

The bigger surprise is Shannon, who has made a career out of creating outrageous characters with no reservations, starting with hyperactive Catholic schoolgirl Mary Katherine Gallagher on "Saturday Night Live." Here she's remarkably restrained, like an athlete pulling back in fear of breaking a hip. At the very least, her funny bone may require an X-ray.

You may remember that Shannon contributed memorable bits to a couple of Thursday-night classics as the woman who didn't move her arms when she walked on "Seinfeld" and as Grace's most ferocious "frenemy" on "Will & Grace." This talented comedienne should have boned up on those performances before trying to join that esteemed club.

njustin@startribune.com • 612-673-7431