Jessica Simpson in Beverly Hills, Calif. on Dec. 10. Credit: Splash News.

Jessica Simpson will not continue her Weight Watchers diet now that she's expecting again, but she will continue to appear in ads for the weight loss company that signed her on as its celebrity spokesperson earlier this year.

"There have been no changes to our business agreement with Jessica," a representative for Weight Watchers told ABCNews.com. "Jessica's successful weight loss prior to becoming pregnant will be featured in Weight Watchers' new 'Expect Amazing' advertising campaign, including a spot with her sharing the happy news."

The 30 second ad in which Simpson says she's pregnant, posted this morning on YouTube and posted below, was shot at the same time as her most recent "Expect Amazing" commercial, where she shows off her 50 pound weight loss. The ads are scheduled to air through winter.

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The Weight Watchers rep also said Simpson "will not be following the program during the pregnancy while her weight and well-being are monitored by her obstetrician, as is recommended for any woman during pregnancy. After she gives birth, Jessica and her doctor will decide when she may resume following the Weight Watchers program."

(While Weight Watchers does not advise pregnant women to follow its program, the jury is out on whether dieting while pregnant is harmful or helpful. A review of studies earlier this year suggested that it could be beneficial if done moderately and if the mom-to-be is overweight.)

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Simpson signed an estimated $3 million deal to be Weight Watchers' celebrity spokesperson in May, the same month she gave birth to daughter Maxwell Drew Johnson. On Christmas Day, the 32-year-old pop star announced she's expecting again, tweeting a photo of Maxwell sitting in front of a sand-drawn sign saying "Big Sis."

Simpson has been vocal about gaining weight while pregnant and struggling to take it off. She posed nude on the cover of April's Elle, cradling her baby bump and weighing 170 pounds. In September, she told Katie Couric she was surprised she didn't shed the bulk of her extra pounds while giving birth.

"During pregnancy, I didn't really think about it," she said about her weight gain. "I thought my doctors were telling me that it was just a lot of water and whenever my water broke my whole entire stomach would go down but that did not happen. All the weight did not come out with the baby."