IN an astonishing transforma­tion, Kirstie Alley suddenly has a smoking-hot body – and friends are whispering that she’s secret­ly resorted to liposuction.

The 62-year-old sitcom queen – whose new TV Land show “Kirstie” debuted Dec. 4 – seems to have won a skirmish in her decades-long battle of the bulge and is flaunting her brand-new figure.

While the 5-foot-8 star has always maintained that she loses weight through eating right and exercise, in­siders believe her “diet secret” may involve a cosmetic procedure.

“Kirstie went from flabby to taut very quickly,” disclosed a close source. “Her friends think she finally bit the bullet and had fat sucked out of her most troublesome spots – her butt, upper thighs and stomach area. Her thighs and butt have always been problem areas. No matter how much she’s lost on yo-yo diets, certain body parts have been resistant.

“Ever since she turned 60, she’s been preaching to friends that women need regular maintenance if they want to keep looking fit.”

In 2009, Kirstie checked into a fat farm after sources told The ENQUIRER her weight had ballooned to 265 pounds. But during a Dec. 4 interview on Howard Stern’s Sirius radio show, the TV veteran claimed that at her heaviest she weighed 230 pounds. She said she lost 25 pounds on her Organic Liaison weight-loss program and 15 more during her 2011 run on “Dancing with the Stars” – dropping her to 190.

She also insisted that she has not had surgical assis­tance. “I don’t have any surgery,” she said. “I don’t think you should be filling your face. I don’t do any of it.”

The source said: “Kirstie gradually put on 10 pounds af­ter ‘DWTS,’ boosting her to around 200. She lost her focus and her figure suffered. She has almost zero self-control when it comes to fattening foods.” During her worst binge periods, she admits to wolfing down 8,000 calories a day along with 12 grape sodas.

“Kirstie’s weight was hovering right at 200 earlier this year when she said, ‘Enough!’” noted the source. That’s when she apparently decided to take extreme measures.

“Although Kirstie claimed she started eating better and busting her butt working out, her friends aren’t buying it,” revealed the source.

“She may have accomplished some of what appears to be a 35-pound weight loss the old-fashioned way, but her pals believe she got down to her current goal, around 165, with the aid of liposuction.”

When asked for comment, Kirstie said that she was flat­tered by the idea that she looks so good people think she may have had a procedure. But she denied undergoing surgery or liposuction.

The portly performer has tremendous incentive for wanting to look her best right now. She’s attempting a career comeback with her new sitcom, in which she plays fading Broadway star Maddie Banks alongside her former “Cheers” co-star Rhea Perlman and “Seinfeld” alum Michael Richards.

As far back as 2007, The ENQUIRER reported that the starch-loving star was considering lipo after her contract with the Jenny Craig diet plan ended and she was frustrated she hadn’t reached her weight-loss goals.

“Today she feels it’s now or never for achieving her dream body,” said the source.

“Although Kirstie isn’t admitting to having lipo, she really doesn’t have a problem with a little body sculpting if it’s the finishing touch on hard work.”.”