Megan Fox's Engagement Ring Designer on Her 'Extraordinary' Design from Machine Gun Kelly

Machine Gun Kelly worked closely with British jeweler Stephen Webster to design a one-of-a-kind engagement ring for Megan Fox which featured a sentimental tie to each of them.

"We were approached by Colson [Baker] to create a very special ring that had true connections to both Megan and himself," Webster tells PEOPLE exclusively.

Almost right away, Kelly knew he wanted to include both his and her birthstones into the design. "During the creative process, Colson had mentioned that Megan's both stone is emerald which he wanted to incorporate in some way along with a diamond, his birthstone," says Webster. The result? Two pear-cut stones sitting on interlocking bands.

"The diamond is a D-color antique cut and the emerald is an extraordinary, completely untreated Colombian gem," he explains. "The design features two interlocking thorn bands, with each side holding one of the two pear-shaped gems."

Getty; Machine Gun Kelly/Instagram

Surprisingly, Webster says that "the resulting ring actually consists of two rings," each created in 18 karat white gold with colorless diamond pavé bands that "perfectly" match the pear gems. "By the use of magnets buried within the gold, [the rings] are attracted to each other and sit together perfectly on the finger," says Webster. "[It's] a detail that is both modern and quite extraordinary."

He shared two photos of the rings — one together, one apart — to his instagram, to help illustrate how they fit together.

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While Webster didn't disclose the cost of Fox's engagement ring, diamond experts estimate it could be worth up to $500,000.

Jewelry designer Mark Broumand says: "This Toi et Moi [you and me] style has a very unique look. The gorgeous white diamond and green emerald really compliment each other. They indeed look to be top quality, putting the ring cost around $300,000."

RELATED: Megan Fox and Machine Gun Kelly Are Engaged and Sealed Union by Drinking 'Each Other's Blood'

Sahar Manley, owner of jewelry label Camilla Seretti, thinks it could be worth a bit more. "It appears that each gemstone is 7 carats, which would make the ring valued at nearly $500,000. Enlisting an expert like Stephen Webster to perfect the custom ring was a smart and thoughtful move to truly master the piece," Manley says.

Megan Fox/Instagram Megan Fox and Machine Gun Kelly

On Wednesday, the Born with Horns artist, 31, proposed to Fox after over a year of dating. Alongside his engagement announcement, Kelly shared an up-close video of the gorgeous emerald and diamond engagement ring he had custom-made by Stephen Webster for the occasion.

In the video, the pear-cut stones shimmer as the Transformers actress, 35, moves her hand. In the caption of his post, Kelly explained the design choice.

"i know tradition is one ring, but i designed it with Stephen Webster to be two: the emerald (her birth stone) and the diamond (my birth stone) set on two magnetic bands of thorns that draw together as two halves of the same soul forming the obscure heart that is our love," he wrote.

Also on Wednesday, Fox shared a post of her own to announce the couple's engagement. Alongside a video of the proposal, she wrote: "In July of 2020 we sat under this banyan tree. We asked for magic. We were oblivious to the pain we would face together in such a short, frenetic period of time. Unaware of the work and sacrifices the relationship would require from us but intoxicated off of the love. And the karma."

"Somehow a year and a half later, having walked through hell together, and having laughed more than I ever imagined possible, he asked me to marry him," she continued. "And just as in every lifetime before this one, and as in every lifetime that will follow it, I said yes.…and then we drank each other's blood. 1.11.22 ✨."

Fox met Kelly while filming her movie Midnight in the Switchgrass. The pair made their relationship Instagram official last summer after she appeared in his "Bloody Valentine" music video. The video came just days after Fox's husband of almost 10 years, Brian Austin Green, 47, confirmed their split.