After being welcomed by pipes and drums at Dumfries House near Cumnock in Ayrshire, the grandfather-to-be will show the Duke and Duchess of Cambridge around an outdoor centre in the grounds.
It is thought to be the first time that the trio will appear at a royal engagement together.
The Tamar Manoukian Outdoor Centre is situated in the 2000-acre grounds of the stately 18th century home that Charles famously “saved for the nation” in 2007.
PHOTO FOR GALLERY
The royals will then declare the centre, which is designed for schoolchildren and uniformed youth services, officially open.
“It is hoped that a slightly younger and fitter male member of the royal party may take the opportunity to demonstrate the rope swing, one of the more challenging obstacles on the course,” said Stephen Kay, head of education and training at Dumfries House .
Kate, who is nearly six months pregnant, will be taking it easy. While in Glasgow on Thursday, Kate revealed that her baby was due “around mid-July” — a more precise hint than the official announcement from St James” Palace.
The party will be welcomed by around 500 representatives of Youth United, an umbrella organisation for youth groups set up by the Prince of Wales in 2009.
Around 400 youngsters and 100 volunteers from the Scouts, Boys” Brigade, Girls” Brigade, Police Service, Fire Service, RNLI, Sea Cadets, Air Cadets and Army Cadets across Ayrshire are expected to demonstrate their skills to the visitors.
Charles, known as the Duke of Rothesay in Scotland, will also open an on-site training kitchen and restaurant.
The Duke of Cornwall famously made a donation of £20m and helped raise funds of £25m to keep Dumfries House open to the public in 2007 when it was at serious risk of closing down.
The Palladian mansion became known worldwide as an architectural “Sleeping Beauty” reawakened from its slumber by the Charles, who saved the property, its contents and estate from ruin.
Their visit will be marked by a fly-past of three Typhoons from RAF Leuchars, a base close to St Andrews University, where William and Kate first met as students.
They both graduated in 2005 with a 2:1. William has a degree in geography while Kate graduated in history of art.
On their way home, the royal couple will stop off in the Lake District to learn about the new Astute Class of nuclear-powered submarines being built for the Royal Navy by BAE Systems.
The shipyard in Barrow-in-Furness, Cumbria is one of the only ones in the world which is capable of designing and building nuclear submarines.