Already a hit with celebs, jewellers say real world brides are increasingly swerving diamonds for stones that reflect their ...

On her own Instagram, Noel promised to share more about the process of co-designing the ring soon, but did reveal in an Instagram comment that the stone is an antique diamond.

"I wasn't involved in the ring design at all. Kevin did it all himself," she tells PEOPLE. "It's gorgeous. I couldn't love it more! It's a vintage diamond ... a series of black-and-white photos ...