The Duke and Duchess of Cambridge are hoping to sail their way to victory this afternoon during their annual King's Cup yachting regatta.
Kate and William are being joined by the likes of Bear Grylls, John Bishop and Helen Glover as they take to the water and go head-to-head in the competition.
The event - taking place in Cowes, Isle of Wight - was brought forward to today because of adverse weather conditions forecast for tomorrow.
Kate, 37, flashed her husband, 37, a cheeky, competitive smile as they arrived at the The Royal Yacht Squadron.
The Duchess looked calm and casual in a £135 knitted stripy top by Sandro, £150 high-waisted trousers by L.K.Bennett, white Superga trainers and a pair of dainty heart earrings by Kiki McDonough.
She also appeared to be sporting a deep tan and lighter locks following the family's recent to Mustique.
Ahead of the race, Kate changed into navy shorts and a white polo top before posing alongside William and The King’s Cup charity ambassadors.
The royal couple will today be skippers of their own boats, competing against six other teams.
They will battle it out for the The King’s Cup trophy, a historical cup first presented by King George V at Cowes’ Royal Yacht Squadron in 1920.
Members of the public are invited to watch the race and prize giving ceremony from the SailGP Race Village, which includes a 500-seater grandstand.
The event will raise awareness and cash for eight of the couple's charities including Child Bereavement UK, Centrepoint, London Air Ambulance, Action on Addiction and Place2Be.
The couple will be joined by Olympic champion rower Helen Glover who will represent the Anna Freud Centre, stand-up comedian John Bishop for Action on Addiction and BBC presenter Katie Thistleton for Place2Be.
While England women's footballer Fara Williams is doing it for Centrepoint, television presenter Dan Snow for London's Air Ambulance Charity and adventurer Bear Grylls for wildlife conservation organisation Tusk.
Both Kate and William are keen sailors and have raced each other at numerous events over the years.
They both rowed when they were teenagers and Kate was part of rowing teams while at school and university.
In May, the couple announced details of this year's event.
They wrote: "The Duke and Duchess of Cambridge will host the inaugural regatta The King’s Cup in summer 2019 to raise awareness and funds for eight of Their Royal Highnesses’ patronages.
"The event, which will take place on Friday 9th August on the Isle of Wight, will see The Duke and Duchess go head to head as skippers of individual sailing boats, in an eight boat regatta race.
"The winning team will be awarded The King’s Cup, a historic trophy first presented by King George V at Cowes’ Royal Yacht Squadron in 1920."
"Their Royal Highnesses hope that The King’s Cup will become an annual event, bringing greater awareness to the wider benefits of sport, whist also raising support and funds for the causes that The Duke and Duchess support."
