In 2006, she proudly paraded her bikini body on Oprah after losing five stone.
But four years on, Kirstie Alley is right back where she started after regaining all the weight and more.
The former Cheers actress is documenting her latest battle with the bulge in a new reality TV show, Kirstie Alley's Big Life, and she has vowed to get down to a slender 9st 7lbs through diet and exercise.
Facing her moment of truth, Kirstie is filmed on the verge of a tantrum after tipping the scales at 16st 4lbs (230lbs).
Starting over: Kirstie Alley begins yet another fitness regime, which is being documented on her new reality TV show, Kirstie Alley's Big Life
Hard work: The former Cheers star admits losing six stone is 'gonna hurt'
'No it's impossible! There's no way,' she squealed.
'I want to weigh 140lbs so that means I have to lose 90lbs. Six stone!
'Funny how the dark, undeniable truth hits like a hammer when you see a number on a scale.
'The truth hurts, but knocking off 90lbs is gonna hurt a hell of a lot more.'
She seeks motivation in the form of a white chiffon gown, which the notorious yo-yo dieter vows to fit into by New Years Eve.
Goal in sight: Kirstie wants to get down to 9st 7lbs
All hands on deck: Kirstie's teenage children Lillie and William have vowed to help their mother get into shape again
Gazing at the floaty, jewelled dress presented by her stylist, she said: 'This inspires me for real. I can't believe I f*****g got f*****g fat again.'
'I spent my whole life thin. I curbed my appetite, but then quit smoking, then quit cocaine and ate tons and tons of food.
'And then I lost all that weight and loved it and had it off for two years. It comes on a lot faster than I get it off.
Weighing in: Kirstie couldn't believe it when she tipped the scales at 16st 4lbs
'What really bothers me the most is that I let myself get that way in the first place and lost it all then I let myself get that way again.
'I have to change my habits now which is hard.'
The former Jenny Craig spokesperson - she parted ways with the slimming company in 2008 as the weight started creeping on again - has this time devised her own diet programme, Organic Liaison.
In her mission, she has enlisted the help of her own handyman Jim, who will be her workout buddy, as well as personal trainer JR, who she hired after ogling his six-pack online.
Motivation: The 59-year-old wants to slim into this white dress by New Years Eve
The series also features Kirstie's two children William, 17, and 15-year-old Lillie, as well as her assistants Kelly and Kyle.
Yo-yo dieter: Kirstie wore a bikini on Oprah in 2006 after losing five stone
At one point Kirstie and Jim - who are strictly platonic - talked about her ailing love life.
When asked when she last had a date with a man she cared for, she replied: 'Ten years. I didn't want too many after the last one because I didn't want anyone telling me how to raise my children.
'But they're at the point now where I would consider having a boyfriend again. I hate the way I feel fat. I hate it.
Kansas-born Kirstie, who is known for being outspoken, also lost her cool while trawling through US tabloid magazines which regularly print unflattering photographs of her out and about in Los Angeles.
'I look like I'm 30 months pregnant!' she said, pointing at one photo. 'I look hideous.
'Oh who am I kidding? I never would have fit into that excellent white dress anyway. Hell I'm even too fat for fat dresses.'
She is hoping her weight loss will help her to revive her flailing career.
She concludes: 'Now I'm forced to decide between getting fit and going for an Oscar - my life's dream - and staying fat and being known for keeping cats and lemurs.'