Light bladder leakage has a new face: Kirstie Alley.

In a campaign for Kimberly-Clark Corp.'s Poise, the "Cheers" actress succeeds Whoopi Goldberg. But rather than play female characters through history as Ms. Goldberg did, Ms. Alley straps on a pair of wings as the Poise Fairy and lurks in the bathroom.

In 30- and 15-second commercials from Ogilvy & Mather, New York, Ms. Alley confronts women who, as their facial expressions seem to make clear, have just experienced light bladder leakage after running on a treadmill or laughing at a joke during a party. Calling out their "drizzizzle," Ms. Alley points out that one in three women suffer from the malady and offers Poise as a better alternative to "period pads."

For K-C, it's pushing the envelope further, advancing the in-your-face humor in a category where discretion once ruled and marketers assumed the less said the better. But Ms. Alley isn't someone who's often at a loss for words. "They came to me with the proposition, and I said: 'Do you think I'm a good match?' I don't have LBL," Ms. Alley said in an interview. "When I found out one in three women had it and they were in their 20s, 30s, 40s, 50s -- it was all whack to me. So I guess I got educated in it, and then I said, 'Yeah, it will be fun.' And I got to wear wings. So I'm in."

Humor has helped K-C gain more than two share points in the adult-incontinence category the past two years, according to SymphonyIRI data from Deutsche Bank.

"A lot of that was just from talking about the condition in a different way with a lighthearted approach," said Rebecca Dunphey, brand director for Poise.

Making things sound less serious actually sells more product in this case, Ms. Dunphey said, because the idea is to steer the brand and conversation away from "incontinence," a more serious issue related to old age.

The ads with Ms. Goldberg, were created by O&M's sibling Mindshare Entertainment and largely spawned the phrase "light bladder leakage," which Google Insights for Search data show barely registered until suddenly emerging two years ago.

"I wouldn't say we're trying to name a condition," Ms. Dunphey said. "It's more trying to create a relatable way for women to talk about it."

Compared to the ads with Ms. Goldberg, which drove home home how common LBL is , the Poise Fairy focuses more on the proper product, contending: "Period pads are for periods. Period."

The strategy makes sense for K-C, which has more than half of the adult-incontinence category, where Poise competes and has seen big gains since the Whoopi ads. However, it holds less than 20% of the market for sanitary pads, which, despite gains by K-C's Kotex in recent years, is still dominated by Procter & Gamble Co.'s Always. Ms. Dunphey said Poise is specifically designed for LBL, while sanitary pads aren't, though women often turn to pads because they are embarrassed to buy products labeled for incontinence.

Ad Age Asks Kirstie Alley Three Questions

What makes someone want to be the face of light bladder leakage? Advertising Age asked Kirstie Alley in an interview, and it turns out she sees herself on a mission of sorts.

It seems like this is a product category it would be hard to get people to represent. Did that go through your mind?

It did. You know you're going to be talking about intimate things. I had to even ask myself, 'Can I speak to this?' But Whoopi [Goldberg] did the account before, and I guess that gave me some street cred on it.

I did a poll on all my friends, probably almost 50 people. I asked when you sneeze and laugh, do you have a little leakage? And they were like, "yes." And I said really? Probably half of them did. More than a third. And I just saw a niche here. I like helping women. I like inspiring them. I like the taboo being taken off certain conversations. So I said, sure, I'm in.

The ads seem very improvisational. Were they?

There was a lot of improvisation. If you go to the website and see the outtakes and the things I tried to pull off, I think they took it down a few notches and tried to be more conservative. But who knows, if I do the account another year, maybe I get to do all my stuff.

Did you have fun?

I did. Anytime I can improv in commercials I do. I don't know if the Poise executives had a good time, but I did. I've never done a commercial where I wasn't improv-ing or writing part of it and creating the thing and jacking around on the set.