Princess Diana's brother, Charles Spencer (opens in new tab), took to Instagram to share a rare portrait of his late mother in honor of her 85th birthday.

The 9th Earl Spencer revealed a beautiful painting of his mother, Frances Shand Kyd, writing, "My mother, it is her 85th birthday. My mother was born in Sandringham, Norfolk, in the same parish, on the very same day that King George V died. She died three days after the 50th anniversary of her marriage to my father. This portrait is in the @althorphouse library."

The portrait depicts a young Shand Kyd with well-groomed blonde hair, bright blue eyes, and a rosy complexion. Naturally, she was compared to a young Princess Diana.

Princess Diana's mother passed away in 2004. At the time, People (open in new tab) reported that Shand Kyd died at her home in Scotland, where she had been hospitalized a few days earlier. The Earl Spencer's mother passed away peacefully this morning after a long illness. This is a sad and private time for the family," he said.

As People noted, "Diana and her mother shared a relationship that is said to have been tumultuous." However, according to the magazine, Diana's mother "wrote thousands of replies to the sympathy letters she received after her daughter's death and actively participated in charities as a way to keep Diana's memory alive."

Last year, Count Spencer published a rare childhood photo (opens in new tab) of Princess Diana on social media. In the sweet photo, Diana is wearing a striped, sunny dress and has her arm around Prince Charles' shoulders. Her shoulder-length blonde hair looks golden in the sun, and both siblings are wearing sandals and socks.