By MARISA GUTHRIE
DAILY NEWS STAFF WRITER

Filmmaker Kevin Smith is well past sweet 16 - he turned 35 a few weeks ago - but until recently he had never been kissed.

On screen, that is.

But in a dream-come-true scenario, he gets to lock lips with his longtime crush in the season finale of The N's high school-set series "Degrassi: The Next Generation."

Smith, not the typical romantic lead, admits to being "insanely nervous" about his first on-screen kiss.

"It's very strange," he said. "They yell 'cut' and you have these weird, superficial conversations to avoid talking about the fact that you were just lip-locked with each other."

Smith's smooching partner is Caitlin Ryan, who is played by Stacie Mistysyn. Smith has been a "Degrassi" fan since his pre-"Clerks" days. He discovered the original series while working Sunday mornings at the QuickStop in Leonardo, N.J., where he eventually shot "Clerks."

"Degrassi," he said, was "the only thing on on Sunday mornings that wasn't a church program."

Caitlin has been the apple of his quirky eye ever since.

"She was a good girl but always sort of misguided. And she's epileptic. And that just seemed like an adorable but manageable handicap to me. You just want to take care of her and make sure she doesn't bang her head or something," Smith said. "And she was always falling for the wrong guys."

In "The Next Generation," Caitlin (as well as Mistysyn) is all grown up and working at a local TV news magazine. Smith and Jason Mewes (playing themselves) go to Degrassi High to film the (fictional) sequel "Jay and Silent Bob Go Canadian, Eh!" Caitlin and Smith get acquainted when she interviews with him for her show. Ever unlucky in love, she is beginning to doubt her relationship with Joey (Pat Mastroianni) and Smith is there to offer a kisser to plant one on.

Smith and Mewes' three-episode arc on Noggin's nighttime 'N' brand begins Friday at 8 p.m. Alanis Morissette also makes a cameo appearance in next week's episode.

Smith, who has made references to "Degrassi" in many of his films, has been trying to finagle his way onto "The Next Generation" for some time.

"I called up [creator Linda] Schuyler and told her I would kill or die to write or direct," Smith said.

"At which point I said, 'I would love to have you do it, but I can't,'" Schuyler said.

"She said you can't do it because you're not Canadian," Smith said. "I've been told no many times in my life, but so far that was the most original reason someone gave me for no."

Since "Degrassi" gets money from the Canadian Television Fund, key creative positions must be filled by Canadians. The actors, however, are not required to be Canadian.

Smith and Mewes are due back in Canada next week to start working on two more episodes of "Degrassi," which will air during the fifth season that starts in October. And Schuyler and Smith are collaborating on a "Degrassi" feature film, which has yet to find a studio home.

Smith, meanwhile, will be back in New Jersey next month to start work on "Clerks 2."

"It was an interesting experience for him to put himself in the hands of another director," Schuyler said. "I didn't realize he was nervous about [the kiss]. I would have never known. I thought he was fantastic. As a producer, I think it is one of my best kissing scenes ever."