The Duchess of Cambridge looked incredible as she against husband Prince William .
The couple went head to head in the King's Cup of the coast of the Isle of Wight, cheered on by Prince George and Princess Charlotte .
Kate certainly looked the part in all the sailing gear, including a smart pair of shorts and a baseball cap.
Many fans were quick to point out how toned her legs looked in the outfit, and they're the result of a lot of hard work from the Duchess.
We know the mum-of-three is really into her exercise and she follows a healthy and balanced diet.
She's previously spoken about how she stays in shape, and said it was all down to her kids.
During a trip to India in 2016, Kate was asked how she shed her baby weight so quickly after the birth of Princess Charlotte .
She replied: "I am running after my kids."
Even though they have a nanny, Kate is believed to be a very hands on mum and does a lot of the work around the house herself.
But she does do a lot of dedicated exercise, and particularly enjoys running and cycling.
She's also reportedly a big fan of CrossFit and yoya.
Kate is said to go out jogging every day, and has a route around the family's Norfolk home Anmer Hall for when they're staying there.
A royal insider told Mail Online: "Kate is an exercise junkie. Pippa and Kate take their toned physiques extremely seriously.
"The duchess is reportedly also a fan of CrossFit and yoga, makes time to go for a run most days, enjoys cycling, and does all her workouts without a personal trainer!"
She's also regularly seen walking in the parks around Kensington Palace, pushing one of the children in a pram.
When it comes to her stomach, Kate is a fan of one particularly gruelling exercise to maintain her defined abdomen.
She swears by the Plank - which is similar to a push-up except a person's forearms rest on the ground instead of their hands - and is dreaded by most gym-goers.
Plank practitioners have to maintain this position for a period of time, with the stance becoming more painful the longer it is held.
A source told Mail Online: "There are three elements, the basic plank, the side plank and the prone sky dive, all of which are positions Kate can hold for 45 seconds or longer and repeat at least ten times each.
"The side plank requires you to balance on your side, holding your body straight with feet together and one arm flexed directly under your shoulder.
"Meanwhile, the prone sky dive plank is slightly less excruciating, as you have to lie on your tummy and gently raise your chest off the floor until your tummy muscles beg for mercy."
She also uses an inflated gym ball to work her abs, an insider said.
After welcoming her two older children, Kate is said to have followed a simple postnatal fitness guide devised by a mum-of-two suffering from depression.
Kelly Rennie transformed her body and created a programme for women like herself - and she's even received a thank you letter from Kate.
Kelly, 35, started her transformation on 2004, when she weighed 11st and wore size 14-16 clothes.
Central to her regime is encouraging mums to stop emotional eating.
The enterprising mum-of-two, originally from Christchurch, New Zealand, dreamed up a fitness guide to help mums trim down, but never imagined she would receive praise from client as high-profile as Kate.
