Princess Diana's 'revenge dress' is taking the world by storm this week as season 5 of the Netflix period drama The Crown is set to unveil the dramatic events that led to the separation of Prince Charles and Princess Diana.
Although there are many historic moments that are expected to feature in the latest series of the show, the latest clip featuring Princess Diana's 'revenge-dress' is becoming a viral sensation.
Photos of Elizabeth Debicki, who takes the role of Lady Diana this season, have shown the actress leaving a car in a black off-the shoulder dress with a low-cut neckline and multi-string pearl choker adored with a huge sapphire.
However, while the 'revenge dress' was no doubt a huge statement from Lady Diana at the time, our jewellery experts couldn't help investigating the story behind that incredible necklace she wore with it.
Here's what we found...
The eye-catching sapphire brooch was a wedding gift from the Queen Mother. The breathtaking brooch previously belonged to Queen Mary, passed down in Royal tradition.
In true Diana style, she redesigned the diamond-and-sapphire brooch as a centerpiece of this incredible seven-strand pearl necklace.
It's been worn on many occasions and is definitely one of her most iconic, statement pieces. In 1985, she was pictured wearing it during a dance with John Travolta at the White House.
Our leading diamond expert, Maxwell Stone, said: "Princess Diana was a clear fan of sapphires and just like her engagement ring, she only wore the most beautiful deep, blue stones. Looking at the image of the huge stone, it could be anywhere from 50 to 70 carats in weight, maybe even heavier.
" With that in mind it could be worth anywhere from £50,000,000 to £100,000,000. This is probably one of the most expensive jewels from the entire Royal collection."