Noel Gallagher's ex-wife was one of four celebrities to give up their home comforts to live on unemployment benefits for the BBC's Famous, Rich and Jobless, reports the Sunday Mirror.
"This was one of the most challenging things I have ever done and made me realise a lot about life," the 43-year-old interior designer said.
"I have never taken anything for granted, but now if I look in the mirror and think, 'Does my bum look fat?' I realise how shallow it seems."
Mathews lives with her daughter Anais, 10, in North London and is engaged to designer Peter Siddell. She swapped her £2m Hampstead house for a flat in Wolverhampton, where she and unemployed ex-con Nick survived on £10 a day. "Unemployed people are not lazy, sitting round on their arses. Being jobless affects your self-esteem and you have to find a way to carry on," she said.
Famous Rich and Jobless, which also features actor Larry Lamb, television gardener Diarmuid Gavin, and model-turned-mechanic Emma Parker Bowles, will air on BBC One on March 9 and March 10 at 9pm.