Prince Charles gifted Princess Diana a stunning blue sapphire ring during the span of their relationship.

Following Princess Diana’s death, the ring was passed on to Prince William’s wife, Kate Middleton.

In the documentary All the Queen’s Jewelry: Heirlooms & Legacy, experts revealed that there’s one simple reason why the Princess of Wales chose the blue sapphire ring.

Sources revealed that the late royal was given several options, but she chose the iconic ring because it was the biggest among the range.

Meanwhile, Princess Diana’s other daughter-in-law, Meghan Markle has also worn some of her jewelry. For instance, Markle wore a huge aquamarine and diamond ring at her wedding reception two years ago.

According to Express, even though the blue sapphire ring is more iconic, it is the aquamarine and diamond ring that’s a favorite of royal fans.

A research conducted by Buckley London, reportedly, revealed that 20 percent of the public liked Markle’s ring more than Middleton’s. However, the reason for this wasn’t revealed.

It is possible that royal fans have been seeing the blue sapphire ring for years because Prince William gave it to Middleton when they got engaged. As for the aquamarine and diamond ring, Markle only wore it recently.

In related news, Princess Diana also made headlines this week after it was announced that Elizabeth Debicki will play the late royal in The Crown.

According to CNN, Debicki will be featured in The Crown Season 5 and Season 6. The Netflix series will revisit Prince Charles and Princess Diana’s marriage, as well as the latter’s demise following a car crash.

Debicki expressed her excitement following her casting.

“Princess Diana’s spirit, her words, and her actions live in the hearts of so many. It is my true privilege and honor to be joining this masterful series, which has had me absolutely hooked from episode one,” the Australian actress said.

Other than Debicki, a slew of actors has also been added to The Crown. Jonathan Pryce will play the role of Prince Philip, while Imelda Staunton will play the role of Queen Elizabeth.

Leslie Manville will also replace Helena Bonham Carter as Princess Margaret.

The premiere for The Crown Season 5 will be in 2022.