The actress known for her cuddly curves unveiled a remarkably svelte figure this week after losing a massive four and a half stone.
After years of trying a variety of faddy diets, Miss Jones, 45, said she had finally done it the old-fashioned way – by counting calories.
Less of Nessa: Ruth Jones this week (left) and as Nessa in 2009 in the hit comedy Gavin and Stacey
It has taken patience, determination and 22 months to get into the best shape of her life.
The newly slim star and creator of Gavin & Stacey is following in the (much lighter) footsteps of Dawn French, Nigella Lawson and Pauline Quirke in dramatically changing her shape.
She showed off her new figure on Monday at the West End preview of One Man, Two Guvnors, which stars her close friend James Corden.
As the eccentric Nessa in the BBC’s Gavin & Stacey, which she co-wrote with Corden, she made a virtue of her size 24 curves. A fuller figure was also essential for her acclaimed role as Carry On star Hattie Jacques in BBC4 drama Hattie.
But after years of being happy in her skin, she decided it was time to lose weight. She is now a size 16.
Miss Jones, who is about to star in Stella, a comedy drama she has written for Sky 1, was frank about what drove her decision. ‘I came back from holiday a couple of years ago – January 2010, and we all overdo it on holiday, don’t we? Something just clicked, I felt this is now or never, I wanted to make a positive change for me, and I haven’t looked back.
Svelte: Ruth in the 'best shape of her life' (left) and playing comic actress Hattie Jacques for a biopic (right)
Not-so-fat friends: Ruth's first major small screen appearance was playing Kelly on the ITV comedy
‘I knew that I had months ahead of me writing Stella and this was my chance to change my routine.
‘It’s taken me 22 months to lose four and a half stone. Although I have done loads of diets in my time I have never done it the old-fashioned way – taking in less calories than I was using.
‘I thought, right, they say 2000 calories a day is the norm for a woman. I’ll aim for 1,200-1,500 a day and see how it goes.
‘Some days are better than others. But if you think about it, there’s calorie values on the back of everything – supermarket sandwiches, chocolate bars – everything.’
Miss Jones, who lives in Cardiff with her husband and production partner David Peet, said: ‘The main thing is that I realised I was going to have to be patient.
'When diets promise you things like “lose a stone in a week” it’s just not realistic. You have to make a decision that if you’ve got a few stones to lose (seven in my case!) then it’s going to take time.’
A close friend added: ‘It has been a lot of hard work. Ruth feels in the best shape of her life, she feels confident and determined but she knows she still has a way to go.’