When Michael Douglas proposed to Catherine Zeta-Jones in 1999, the Fatal Attraction star presented her with the most breathtaking sparkler.
Over the course of their 24-year marriage, the Chicago star has rocked her gorgeous engagement ring on the red carpet and in interviews. But it is a different, nearly identical piece from her collection that has caught our eye of late.
"Catherine’s engagement ring is a gorgeous 10-carat-side-set marquise diamond ring set in platinum and designed by Fred Leighton," Nilesh Rakholia, jewellery expert and founder at Abelini, tells us, estimating the ring to be worth $342,000-$373,000 (£275,000-£300,000).
"The shape of the diamond dates back to the 18th century, with King Louis XV of France paying for jewellery to create a completely unique diamond in the shape of his mistress' lips. The cut has been developed and modified since, evolving into the cut it is known as today."
"While other classic cuts such as round or princess are often more popular choices for engagement rings, the marquise cut diamonds offer a bold and striking alternative that makes a true statement. This is certainly in keeping with Michael’s proposal back in 1999, on New Year's Eve at his luxurious home in Aspen."
The stone itself is also a symbolic one - after all, diamonds are a girl's best friend for a reason. "Diamonds are associated with strength, love and health - the perfect jewel for an engagement ring with the promise of spending the rest of your life together," Nilesh explains.
"The elongated shape of the marquise cut also allows for versatility for various setting options, making this diamond completely unique - a true symbol for a one-of-a-kind love."
The ring has sat pride of place on Catherine's ring finger for over 20 years without going out of style, and yet it is hitting a major jewellery trend for 2024.
Nilesh tells us: "A marquise's unique shape provides the perfect balance between a modern and vintage aesthetic. Vintage jewellery seems to be having its moment this year, with Pinterest searches for 'vintage wedding rings' seeing a 200% yearly change and with many stars adorning vintage pieces on the Oscars carpet last month."
Despite its magnificent beauty, it isn't the only incredible diamond in Catherine's collection. The Mask of Zorro star took to Instagram earlier this month where she looked chic in a black and white image wearing oversized sunnies and resting her chin on her hand, showing off an enormous diamond ring which could have easily been mistaken for her engagement ring.
Jon Richard of Jon Richard Jewellery gives an insight into this spectacular piece. "An estimated 10-carat brilliant-cut round diamond with a gleaming pave diamond halo in platinum, valued at approximately $435,000 (£350,000), it epitomises the 2024 trend of striking jewellery," Jon explains.
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"Catherine Zeta-Jones' ring perfectly captures the essence of opulence and allure, setting the standard for show-stopping elegance."