Kirstie Alley tweeted that she has lost 20 pounds. Credit: Cindy Ord/Getty

Lean lady! Kirstie Alley is slimming down, shedding 20 pounds while back on the Jenny Craig weight loss system. 

The Kirstie star, 63, took to Twitter on Tuesday, June 24, to celebrate her fitness achievements. "I'm down 20 lbs*!!! That's like losing 3 lemurs!" Alley wrote, attaching a photo of three lemurs. She keeps the furry creatures as pets. "Thanks @JennyCraig!!*typical loss 1-2 lbs a week." Despite that weight loss milestone, the Cheers alum has yet to share any social media snapshots of her slimmer figure, nor has she been photographed while out and about.

"On my way to my 30 lb weight loss," Alley continued. "Join me!!!! FEELS GOOD!!! Typical weight loss is 1 to 2 lbs a week… @JennyCraig."

The actress announced plans in April to get back on the diet program a decade after she started as a spokeswoman in 2004. Alley is hitting her weight loss goals, as she said at the time of the announcement that she was hoping to lose 20 or 30 pounds. 

"I'm not like, circus fat," Alley says in a campaign ad for Jenny Craig, adding that she rejoined to become slightly svelter. 

"I feel amazing because I feel healthy and I feel happy," she told Matt Lauer while on The Today Show in April. Alley famously lost 100 pounds in 2011, when she showed off a toned body and celebrated her success.