Heidi Klum's kids don't get upset about her bikini posts on Instagram - because they've seen her ''sunbathing topless''.

The 44-year-old supermodel - who has children Leni, 12, Henry, 11, Johan, nine, and Lou, seven, with ex-husband Seal - recently shared a number of photos of herself in her swimwear from a family vacation in St. Barts, and she claims her children don't mind how open she is with her fans because they're used to her skimpy outfits.

She said: ''They know I worked in the lingerie industry for a long time.

''They've seen me sunbathing topless at home. Obviously not when their friends are coming over... So, yeah, they're not like, 'Oh, my God! What are you posting?!' ''

Heidi - who is dating art curator Vito Schnabel - admitted she feels at her sexiest now because she's still got her holiday tan.

She told 'Extra': ''Because I came back from vacation and I still have my tan... turn around from every angle, everything is nice and brown. I feel like a marshmallow that's just been roasted.''

Despite her envious figure, the 'America's Got Talent' judge insists she doesn't have a consistent workout regime and she will indulge in her favourite calorific treats whenever she fancies them.

She said: ''Whenever I can [work out], I do, and when I can't, I can't. I don't beat myself over it... I'll go in the attic where I have my little treadmill... You don't need a trainer, you can really do things yourself.

''I eat what I want to eat, but not all the time. I don't eat burgers and pizza and chocolate all the time, but I do eat it!''

Meanwhile, the blonde beauty revealed her show 'Project Runway' will be setting a new challenge for the designers in the upcoming next season.

She explained: ''We have models of all sizes, which is something for all the seasons we have never done... A lot of the designers were not happy about that. If you want to be a good designer, you need to be able to design for everyone.''