In a candid six-page feature for Cosmpolitan UK, Willoughby - who poses on the back of a Harley-Davidson - revealed that she would rate her looks a "7.5 to 8" out of 10.
"There's always something I'd like to change but I try not to focus on it too much," she said. "Over the past few years I've learnt that my body is capable of giving birth to two amazing children, which is a wonder in itself.
"And I think if the way you look is your entire focus, you're doomed. There should be other things in your life."
On getting back into shape after the birth of her daughter Belle last April, Willoughby said: "I don't think I am in shape. Obviously it's something I think about - after growing a baby for nine months, you want to get back to yourself - but I think that signifies more than just weight.
"You need a bit of you-time and you want to get back into your jeans. But as for diets, no. I just sort of went back into work and I watch what I eat, mainly because I'm too lazy to go to the gym."
Asked when she feels her sexiest, the 31-year-old said that there was an "obvious answer", responding: "Doesn't everyone feel at their sexiest when they're having sex?!
"I've always found that if you dress sexy, you feel sexy. Underwear has got a lot to do with it. It can make you feel sexy even if you're wearing jeans and a baggy jumper. Also, I don't know whether this makes you sexy or not, but I think one of the most important things is being content and knowing when you've got a good thing and enjoying it at the time."
"Obviously I'm used to live TV with This Morning, but entering into any new show is scary and I'll definitely be nervous on the first live show. It really helps that I'm doing it with Reggie [Yates] - we started at CBBC together, although this is the first time we've actually worked together."
The full interview appears in the April issue of Cosmopolitan UK, on sale Thursday, March 1.
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