Say what you want about Kate Middleton, she always looks flawless.

The duchess has a reputation for appearing put-together no matter what the occasion. Now a royal insider has revealed that Kate's underwear choice has a lot to do with her pristine outfits. Etiquette expert Myka Meier, who was trained by a member of the queen's personal staff, says that the key to a neat outfit is in the right bra and knickers. Keen to avoid any VPL or bra outline, Kate tends to opt for a strapless, all-in-one bodysuit, Myka has explained. "Underwear and bras are considered private intimate wear, and for royals to put intimate apparel on display would simply not be done," she told the Sun. Another trick Kate uses, according to Myka, is to have her underwear sewn into her clothes for her for a completely seamless look. What's more, the duchess is said to be a fan of affordable undies and likes to buy her shapewear at UK department store John Lewis, reports Glamour. Of course, this isn't the first clothing hack of Kate's that we've heard about. The mum-of-three, who spends most of her working life in high heels, reportedly puts sticky pads on the bottom of her feet when she's wearing stockings and heels to stop her feet from slipping out of her shoes. Even more ingeniously, it's rumoured that she copies the queen's trick of sewing weights into her skirt hems to prevent them blowing up in the wind.