Charles Spencer shares never-before-seen family photograph

Charles is the younger brother of the late Diana, Princess of Wales

Charles Spencer delighted royal fans this week when he took to Instagram to share a previously unseen family photograph. Charles – the younger brother of the late Princess Diana – took to social media to share a black and white image depicting his grandmother and father, taken around 1937. His followers were quick to comment on the strong family resemblance between his father John Spencer, the 8th Earl Spencer, and John's maternal grandson, Prince William. "Strong resemblance to yourself and Prince William. Great pic!" one remarked. "Oh my stars, that could be a very young William!!!" another added. Others noted the similarities between Charles' grandmother and his eldest daughter, Lady Kitty Spencer, with one stating: "Grandmother and Kitty are twins!"

Charles Spencer shared a photograph of his father and grandmother together

Charles was the youngest child born to John Spencer and his wife Frances Shand Kydd, known as the Viscount and Viscountess Althorp. He had three older sisters, Lady Sarah McCorquodale, Lady Jane Fellows and the late Diana, Princess of Wales, to whom he was very close. Charles – who is a godson of the Queen – inherited the ancestral seat, Althorp, in 1992 following the death of his father. The Spencers have called the estate of Althorp House home for over 500 years, and aside from being Diana's childhood home, it's also her resting place. In keeping with tradition, Charles – a father of seven – has confirmed he will be passing Althorp on to his eldest son, Louis.

MORE: Charles Spencer's children Kitty, Eliza and Louis bring glamour to Windsor

Pictured standing alongside the portrait of his wife Karen

Earlier this week, 55-year-old Charles took to Instagram to share a spectacular portrait of his wife Karen, based on a photograph taken at the wedding of Prince Harry and Meghan Markle in May last year. Charles and Canada-born Karen were married at Althorp House in June 2011, and have one child together, Lady Charlotte Spencer, born in July 2012. Charles has four children from his first marriage to Victoria Lockwood, which lasted from 1989 until December 1997; Lady Kitty Spencer, Lady Eliza Spencer, Lady Amelia Spencer, and Louis Spencer, Viscount Althorp. His second marriage to Caroline Freud lasted from 2001 until 2007, and together they share two children; the Hon. Edmund Spencer and Lady Lara Spencer.