by Scott D. Pierce

You'll have to excuse Sarah Michelle Gellar if she's a little bit defensive about her show, "Buffy the Vampire Slayer." After all, it remains one of the best-written, best-acted programs on TV — and, in many quarters, it has never gotten the respect it deserves.

Which is why Gellar has no patience with people who can't see past the admittedly offbeat title and think the show is something far different from what it really is — people she described as "stupid people," rather bluntly (but sweetly).

"I don't mean to be rude, but I think that people that would say that — it's just ignorance," Gellar said. "Sometimes people look at a title. I know when (executive producer) Joss Whedon was first creating the show... people didn't want a show named 'Buffy the Vampire Slayer' because they were afraid it would turn people off.

"This show is the most wonderful mix of brilliant, witty writing and phenomenal performances and evolving stories. If people say they won't watch it... that really is just ignorance."

And if some people turn up their nose at a show called "Buffy the Vampire Slayer," what will they say about this coming Tuesday's episode (7 p.m., UPN/Ch. 24) — officially, it's titled "Once More With Feeling," but, unofficially, we're calling it "Buffy: The Musical."

That's right. An hourlong episode — written and directed by series creator/executive producer Joss Whedon — in which the cast performs musical production numbers.

Skepticism among even fans of the show is understandable. Heck, I thought it was a terrible idea, and I love "Buffy."

And I was wrong. This episode is a triumph — maybe the best ever, which is saying a lot. "Once More With Feeling" is better than any movie musical in memory. It's better than a lot of Broadway musicals.

It's funny and shocking and heartfelt. It mocks itself without becoming a parody. And it makes sense within the "Buffy" universe that all these people would suddenly be singing and dancing. (I won't give it away, but there's a demon involved.)

And this is not a stand-alone, let's-go-out-in-the-barn-and-put-on-a-musical show. "Buffy's" ongoing story arc is advanced in big ways. HUGE ways.

All the regulars have their moments — Gellar, Nicholas Brendan (Xander), Emma Caulfield (Anya), Anthony Stewart Head (Giles), Alyson Hannigan (Willow), James Marsters (Spike), Amber Benson (Tara) and Michelle Trachtenberg (Dawn). Not all are of equal vocal talent — Head, Benson and Caulfield turn in the best performances, but even the non-singers are made to look good.

It's not particularly scary, but there are some big surprises — including one that will have fans of the show picking their jaws up off the floor.

This is the sort of risk-taking TV that the Emmys ought to reward but won't. Whedon was absolutely right when he said, "There are some people who never take genre shows seriously. It's a prejudice... that I'll never understand. Because (they think) anything to do with fantasy turns them off, and anything that's humorous must not be meaningful.

"So this year (the 'Buffy' cast) are all going to be doctors," he joked. But, no joke, Tuesday's "Buffy" is the best thing to hit TV in a long time.