Lady Penny Lancaster-Stewart wants someone to tell her she's gained weight.

The 46-year-old model - who has sons Alistair, 11, and Aiden, six, with husband Sir Rod Stewart - knows she's not as slim as she was before she has her kids but can't seem to motivate herself to change her diet and exercise habits, so she wishes her spouse or even a doctor would prompt her into doing something about her extra pounds.

She said: '' I've always been into fitness but since having children, I've been a bit lazy and made every excuse there is not to go to the gym. I have a huge appetite, everyone tells me, and I've been putting on the pounds and wondering why I'm not losing any.

''It's because I'm not eating well enough and I'm not exercising and I can't find the motivation...''

When fellow 'Loose Women' panellist Jane Moore pointed out that the 'Maggie May' singer loves her regardless of her size, she replied: ''That's the good thing, it's sort of good and bad, I want someone to go, 'Ooh Penny you've put on a bit', and that would motivate it, but I manage to disguise it, I wear clothes that suit me...

''If the doctor said I'm feeling tired because I'm eating too much sugar, or this, I'd do something.''

But Penny doesn't think anyone is likely to make any comments about her weight because she has learned how to disguise any extra gain.

She added: ''The thing is, when I say 'I've put on a stone'. People say, 'Oh you're tall you can get away with it'. But I'm not getting away with it, I've got the bra fat and the tummy thing.

''It's hair and make-up and because I'm 6ft 1 it covers it up. My jowls are getting chubbier.

''Please don't feel sorry for me but I have put on two stone since having my last child, it does distribute itself evenly I suppose.''

And the blonde beauty was horrified to recently read a magazine article urging people to follow her diet and exercise regime.

She said: ''I read an article the other week that said, 'Follow Penny's fitness regime, she works out five times a week and I thought [gasp] 'I don't'. ''