When you're on a David E. Kelley show, you get used to facing unexpected twists. But Boston Legal's Monica Potter wasn't ready for this one: Just a few months into her deft portrayal of quick-thinking attorney Lori Colson on ABC's Practice spin-off (Sundays, 10 pm/ET), she got a big surprise — she's pregnant.

"There's no hiding it [now]," Potter, 33, tells TVGuide.com. "My gut's getting big... I could pass it off as beer and say that I've been out late [a lot], but I can't blame it on that."

Well, actually, the credit really belongs to her fiancé,

Chris, an orthopedic surgeon she met after friends of hers encountered the M.D. in a Los Angeles hospital and decided he was too good not to fix up.

"They invited him to a party," explains the Ohio native, "and when he walked in, I liked him right away. He sat down and we were talking, and a few minutes later we were... makin' out. And then we got engaged two months later." The couple plan to get married in June. (FYI, Potter has two sons, Daniel and Liam, from a previous marriage.)

Meanwhile, she continues with her caseload on Boston Legal, well aware that even the best acting gigs on TV are tenuous at best. She still misses her friend Lake Bell, who exited the series earlier this year when Candice Bergen came aboard. "I started crying," she recalls of the day she heard about Bell's release from the show. "She was really fun to be around. We would just sit there and laugh."

Luckily, another of Potter's colleagues keeps her smiling. "When I met Bill [Shatner]," says Potter, "the way he laughs — sometimes he'll have his hand on his stomach — my dad did that all the time. There are a lot of similarities, and it's weird because my dad just passed away. And so now, I look forward to sitting down and talking to Bill and hanging out with him. It's kind of a neat thing. He's just a cool guy."

In return, Shatner says of his costar, "She's a sweetheart, a delight..." then adds, as only the wisecracking vet could, "...and she's got the most perfect profile I've ever seen."

No doubt, her middle profile will continue to expand, but the producers have no plans to write her pregnancy into the show beyond a recently shot scene in which Denny Crane, Shatner's overly blunt character, calls her "chubby."

As for the Patch Adams actress' own thoughts on her Legal future, she says, "I would love to strike a balance somehow. I always put my family first, and if it was possible to do both, that would be great."

Considering Kelley's family-first attitude — the producer has a nursery at the studio for his employees' kids — that shouldn't be a problem.