If watching Jessica St. Clair on stage is even half as funny as having a telephone conversation with her, We Used To Go Out is going to be the sleeper hit of the festival.

Together with long-term comedy partner Jason Mantzoukas, with whom she’s performed over the last 10 years, St. Clair is bringing the already well-received 50-minute show about a doomed relationship to Theatre 99 — and if you know what’s good for you, you’ll be there too.

Current members of the Upright Citizens Brigade Touring Company — “we’re kind of the graduating class; we’ve been there since it opened” — St. Clair and Mantzoukas met at artsy Middlebury College in Vermont in the mid-’90s and immediately hit it off. The first show they wrote together, I Will Not Apologize — where “basically, every scene is an argument,” laughs St. Clair — found critical success at HBO’s U.S. Comedy Festival in Aspen, and resulted in the duo flying out to Los Angeles to pitch several television shows.

“Once we were out there, what we found ourselves talking about most of the time was whether or not Jason and I were a couple,” recalls St. Clair. “And we’re not — I’m actually getting married in July — but people were obsessed! They wouldn’t stop asking about it! They’d say, ‘Why are you guys working together but not sleeping together?’ I guess we’re one of the very few male/female comedy duos around, and that kind of piques a lot of people’s interest.”

But the nosiness paid off when it came time for St. Clair and Mantzoukas to start working on their next show. “We said, ‘OK, what if we were a couple and we broke up?” she recalls. “At that point in our lives, all our friends were either getting engaged or breaking up, so we had all this great material to draw from. It made the show incredibly easy to write because we just listened to all our friends’ stories and wrote them down when we got home. In fact, at one point, I invited one of my girlfriends, Kristin, to come and see the show, and halfway through, I remembered that I’d actually transcribed one of her stories verbatim to use as part of the act. Jason said that instead of being called We Used To Go Out, the show should be called Kristin Arends, This Is Your Life.”

The premise of We Used To Go Out hinges on a couple in their late 20s whose relationship is on its last legs. “You know, the kind of relationship that should have ended a year or two ago, but just dragged out instead,” says St. Clair. In an effort to resuscitate an obviously dwindling interest in each other, they try a number of different tactics to spice things up. “They look at porn on the internet, they talk about inviting a lesbian couple to join them in bed — that kind of thing,” says St. Clair. “Of course, it’s all a disaster, and they break up in the middle, and then the character played by Jason gets depressed and wears the same sweatpants for three weeks and only eats yogurt. But that’s kind of funny, too.”

Though they’d originally assumed the show would appeal most strongly to audiences in their 20s and 30s, a rave review in The New York Times brought an older crowd, “which was kind of surprising, because we were performing in, like, this dark, underground basement,” says St. Clair. “We’ve even seen people in their 20s coming with their parents — and, you know, more power to them, because there’s some pretty upfront material in the show. Of course, we all like to think that our parents have never gone through any of the things we’ve been through, but they obviously have.”

The beauty of the show, in fact, is its unabashed, undaunted look at the human condition — after all, beneath all the laughs and the snickers and the giggling, We Used To Go Out gets right to the heart of the fact that there isn’t a person among us who hasn’t questioned their relationship, had a fight with a partner, or gone through a hideous breakup. “A lot of comedy is all ‘Look at how funny we are! Look at how clever we are!'” says St. Clair. “Our show is more like ‘Look at how ridiculous we are, with our fights and our doubts and our hating each other.’ Of course, the details are embellished and the storyline is cobbled together from a hundred breakup stories, but it all comes from a very true, very honest place.”

And it’s a place we’ve all been to, of course. Even if most of us decided not to do the lesbian couple part.

WE USED TO GO OUT • Piccolo Spoleto’s Piccolo Fringe at Theatre 99 • $15 • May 31 at 7 p.m.; June 1 at 9:30 p.m.; June 2 at 5 p.m.; June 3 at 6 p.m. • 1 hour • Theatre 99, 280 Meeting St. • 554-6060

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