After posting the black-and-white picture, royal fans were quick to spot the striking resemblance to a current and young member of the Royal Family – the Prince and Princess of Wales’ eldest son, Prince George.
Charles Earl Spencer, 58, took to his social media accounts to mark his late father’s 99th birthday.
The 58-year-old currently at Althorp House in Northamptonshire.
The monochrome inage shows John as a 16-year-old cadet captured in 1940.
Taking to Twitter, Charles tweeted: “On his 99th birthday, today, a glimpse of my father as a 16-year-old cadet in 1940. 4 years later he’d be Mentioned in Despatches for his role as a tank commander in the Normandy invasion.
A third user simply commented: “Prince George.”
Another wrote: “The apple doesn’t fall far from the tree.”
Charles also shared a photograph of his late mother, Frances Shand Kydd on Friday.
Sharing a painting of Frances to mark her 87th birthday, royal fans also spotted her uncanny resemblance to Charles’ late sister, Princess Diana.
Royal fans were stunned by the portrait, with one commenting: “Diana’s beauty shows through your mum”.
Another wrote: “She’s so beautiful. Diana definitely looks similar to her.”