Charles, 72, and Edward, 56, showed their deep connection, as they chatted and laughed with one another at the Berkshire racecourse on the opening day of the meet.
The future King is only two years older than his sister, Princess Anne, and the royal siblings were incredibly close growing up, particularly when the Queen and the Duke of Edinburgh were away on overseas tours.
Charles and Anne were 12 and 10 respectively when Prince Andrew was born in 1960 and were often pictured entertaining their baby brother.
Prince Edward arrived four years later and despite the age gap, he has a close bond with his older siblings.
Take a look at Prince Charles' sweetest moments with his brothers and sister.
WATCH: Princess Anne has the best reaction as she's mistaken for her brother, Prince Charles
Charles and Edward embraced one another warmly as they met in the Royal Box at Royal Ascot 2021.
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Charles gave Anne a helping hand with her hat at the Order of the Garter ceremony in Windsor in 2005.
A grinning groom, Prince Edward, made his way to St George's Chapel at Windsor Castle, flanked by his brothers, Charles and Andrew, on his wedding day to Sophie Rhys Jones in June 1999.
Prince Andrew and Prince Edward laugh together during the Diamond Jubilee Thames River Pageant in 2012 to mark the 60th anniversary of the Queen's ascension to the throne.
A five-year-old Edward sits on his brother Charles' lap in 1969 at the Queen's Norfolk home in Sandringham.
That year, a fly-on-the-wall documentary about the royal family was shown on TV, which followed the Queen and her family in their public and personal lives. After repeated showings on TV, Her Majesty effectively ordered that it never be shown in public again without her permission.
During another off-duty moment, Charles and Edward were pictured giggling as they tried their hand at go-karting around the grounds of Windsor Castle.
And Princess Anne couldn't resist getting in on the action, as the royal siblings raced one another.
The royals like ski breaks during the winter months and we adore this sweet photo of Prince Philip laughing at Charles and Anne sledging in Malbun, Liechtenstein in 1965.
How cute is this image of Charles and Anne laughing when they were kids? The photo was taken during one of the royal family's summer breaks in Balmoral in 1952 – the year that their mother Elizabeth became Queen.
The reactions on Charles and Anne's faces here are priceless as their dad Prince Philip gives them a big push on a swing within the grounds of Balmoral Castle in 1955.
A doting big brother! Charles kisses his newborn sister Anne after her birth in 1950.
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