How Mom-of-4 Heidi Klum Keeps Her Legs Looking Fabulous at 43

Heidi Klum's legs aren't just the most wanted, they're also worth millions.

Back in 2011, Klum's legs were insured for $2.2 million. One leg for $1.2 and the other for $1 million, because "I have a big old scar on my knee," she says.

At 43, Klum's legs are still covetable. "I always enjoyed, and I still do, wearing super short miniskirts showing off my legs," she tells PEOPLE. "I think legs are sexy. I do like to put a focus on my legs when I go out or when I get onto the red carpet. I do."

She says her legs have aged well because she works out now more than ever. "When you get older everything changes," she says. "I have four children and I gained 45, 50 lbs. with each of them… [It's] gravity and having four pregnancies where your body stretches in and out four times, so I do more now than I have in my twenties or my thirties."

"My thirties is when I started to take care more of my body in terms of changing my eating habits, eating much healthier, leaner," she says. "Obviously I still have burgers and fries and all of that stuff, but not as much as I did in my twenties. I mean that's not true, I still love my fries, I just don't have my fries… When I was in my twenties I did not think about any of this kind of stuff. None of it."

These days, Klum says, "I run a little bit. I don't run like super fast or super far," she says. "But it's not really about how fast you do it. For me it's just like doing it, period." She also climbs on the treadmill wearing ankle weights, and does rear-focused "butt lifts" that also tap her inner thigh area. "It's always good to keep the muscles underneath working so that it is nice and toned," she says. "Toned is good."

But if you're not lucky enough to be blessed with supermodel genes (and a supermodel workout plan), Klum has a couple of fixes, one of which you can get at the drug store.

"If you don't feel super-confident because maybe you are still a little scared to show your legs, I love fishnet stockings," she reveals. "Fishnet stockings look always fantastic. You can buy them in your skin color, or in black… You'll see a lot of performers [on stage]. what do they wear? Fishnet stockings. It's like a trick, because your leg always looks much better. So you get the illusion of a nude leg, without having an opaque stocking. You still get the illusion of seeing your skin."

"I love Sally Hansen Airbrush Legs," she says. "You have to find your color so that it's not too orangy or too pasty or too chalky looking, but they do have great colors… You have to just dry [off] a little bit before you put your clothes on, you have to like walk around without anything on for a little while, and then you put your little miniskirt on. It definitely makes your legs so much better looking… [There are those] little veins that pop out on [my] legs, so I like to cover them."