The moment that everyone who has ever watched an episode of "The Nanny" knew would someday arrive is here - Fran (Fran Drescher) and Maxwell (Charles Shaughnessy) finally get engaged.

And Drescher, who not only stars in the show but is one of its executive producers, firmly believes this turn of events will breathe new life into the series."This is a natural," Drescher said in a recent interview with TV critics. "The one question that's been asked more than any other over the five years that we've been in business is, `When are they going to get together?' "

And the answer is tonight at 7 on CBS/Ch. 2.

The premise of "The Nanny" had very middle class, very Jewish Fran Fine going to work as the nanny to very upper-class Maxwell Sheffield's three children. The show would never be confused with "Frasier" or "Mad About You" - it's something more akin to "The Beverly Hillbillies," with its outlandish, over-the-top writing, sight gags and sheer silliness.

It's also the sort of program that brings "ooohs" and "aaahs" from the studio audience for the mushy stuff. And there's plenty of that in tonight's episode.

The fact that the two main characters are going to get married won't change the show significantly, Drescher insists.

"Because the characters are so different, the fact that they're getting married is only going to ignite more conflict and create more situations where she is a fish out of water - where she is the blue-collar girl in a blue-blood world," Drescher said. "It's just going to point up the initial differences between the characters that might have gotten slightly defused over the years. They're going to have to work out the kinks all over again."

The decision to have the couple get engaged at this point does, however, seem more driven by ratings than by any creative impulses.

"Historically, it hasn't been an advantageous thing to have the couple in a sitcom that has as much sexual tension as we have had on the show actually tie the knot," Drescher said. "But I think that, in the name of competition, it's necessary to play our trump card."

And "The Nanny" is indeed facing increased competition. Wednes-days at 7 p.m. is a tough time slot, what with "Spin City," "Beverly Hills, 90210" and "Star Trek: Voyager" to contend with.

"This is the right time to do it," Drescher insisted. "We are just playing our trump card, and we're lucky that we have one to play. The competition is so great that we have to give the audience something new and thrilling to watch.

"I feel very bullish."

She's also hoping that the change will bring back some of the audience that has drifted away in the past year or two.

"Historically, I think the fifth season - if they last that long - is a time when shows make changes," Drescher said. "That's when `Mad About You' decided to get pregnant, and it revitalized the show in a way that became interesting and exciting to some viewers that might have strayed."

And the show won't change that much, Drescher assures us. Heck, the two characters will even continue to address each other the way they always have.

"I think we're going to use `Mr. Sheffield' and `Miss Fine' as pet names because I can't bear the thought that they'll never call each other `Mr. Sheffield' and `Miss Fine' anymore," she said.

The engagement won't drag on endlessly. Fran and Maxwell will get married in the final episode of the season, which will air sometime in May.

And, assuming there is a sixth season - a pretty safe bet - more changes are in store.

"Next year, she'll get pregnant," Drescher said. "Fran Fine is going to be very funny pregant."

As a matter of fact, Drescher is already looking beyond next season for the show.

"I think it's got a couple more seasons in it," she said. "They're going to get married and that'll open up a whole new can of worms. Then she'll get pregnant and that's going to be a whole new thing for her. Then they'll have the baby and they'll have to raise a kid from scratch. And, once again, that will point up them as an odd couple.

"I think as long as we're driving down this road, I see us comfortably doing at least a sixth and seventh season."