Credit: Ray Tamarra/Getty Images; Michael Buckner/Getty Images

"I've lost a million pounds!" Kirstie Alley joked to Us Weekly while on Dancing With the Stars in April.

Maybe not, but the former Fat Actress star, 60, has shed 100 pounds since being on the show -- going from a size 14 to a 6.

"I feel like I'm back in my element," Alley told Entertainment Tonight. "I honestly didn't realize what I looked like."

So how did Alley -- who parted ways with Jenny Craig in 2008 after she struggled to maintain her 75-pound weight loss -- manage to stay slim this time around?

"She didn't crash diet. She wanted to lose weight the right way, but nothing was working for her, so she created Organic Liaison," a source tells the new issue of Us Weekly (out now). The slim star developed the supplement plan with doctors and nutritionists in 2010.

Alley, who came in second place on Dancing With the Stars, relies on appetite-suppressing drinks to stick to a healthy diet -- and she's keeping fit by dancing up to three hours a day with pros recommended by former partner Maksim Chmerkovskiy.

"She's in an amazing place," the source says.