NEW YORK (AdAge.com) -- What do you do when your endorser works too well?

If you're Jenny Craig, you hire another fat actress. Kirstie Alley helped the weight-loss chain reap 1 billion media impressions last year and nearly double its number of customers after she went on its program and shed 75 pounds.

But two years later, she has no weight left to lose. So Jenny Craig has signed another classic TV star: Valerie Bertinelli.

Successful formula
Following the formula that has helped the once-faded diet plan curry favor with a contemporary audience, the chain is inviting the public to share in the weight-loss story of "One Day at a Time" actress Ms. Bertinelli. She was featured on "The View," "Rachael Ray" and "Larry King Live" and on the cover of People during the first week of the campaign. In initial ads, Ms. Alley is featured as her diet mentor.

The Kirstie Alley campaign was "dramatic in that it has helped change consumers' perception of the brand to a more contemporary choice," said Scott Parker, Jenny Craig VP-marketing. The Nestle chain would not break out sales figures, but Mr. Parker said from the start of the Alley campaign in January 2005 through December 2006, Jenny Craig doubled its number of weight-loss customer leads.

Mr. Parker attributes some of the success to a more dynamic media strategy that included adjusting spending levels weekly to match the relative effectiveness of ad copy, created by JWT, New York. "The campaign clearly gave us traction and allowed us to spend more media at profitable levels," Mr. Parker said. Spending overall for Jenny Craig grew roughly 25% during the past two years, he said. TNS Media Intelligence numbers show Jenny Craig spent $27 million in media in 2005, a number that jumped to $36 million in 2006.

Lowest weights at highest peaks
Key to the campaign's success was the PR strategy, crafted with Jenny Craig PR firm Lippe Taylor and orchestrated to "reveal" Ms. Alley's weight-loss efforts at seasonal peaks in its business: in January, April and September. Covers of People, Ladies Home Journal and Good Houskeeping, as well as two Oprah appearances (including one in which a trim Ms. Alley donned a bikini) helped seed the brand.

According to John LaRosa, research director for diet-research firm Marketdata Enterprises, the Alley campaign likely helped Jenny Craig a lot. But he said most commercial diet chains, including Weight Watchers and NutriSystem, have gotten a boost from delays in prescription weight-loss drugs coming to market and the demise of the low-carb trend. Current sales figures for Jenny Craig are unavailable. The chain's 2005 sales were $462 million.

Mr. Parker said the Bertinelli campaign debut marked the highest level of calls to Jenny Craig in its history.

Such an auspicious start gives him hope the new campaign will bear as much fruit as its predecessor, especially because it incorporates lessons learned. Instead of only shooting commercials featuring weight-loss updates of Ms. Bertinelli three times a year, Jenny Craig will update existing spots with visuals of Ms. Bertinelli's progress every few weeks. In addition, JennyCraig.com will feature Ms. Bertinelli in written and video blogs; entries will be sent to Jenny Craig clients at various stages of their weight losses. It's hoped this tactic will appeal to the younger audience that Ms. Bertinelli, nine years Ms. Alley's junior, is expected to attract.