More than 600 guests watched as Harry and Meghan exchanged vows and rings at St George's Chapel on May 19, 2018. But of all the guests, Jessica Mulroney, played the most significant role.

Part of Meghan's everyday arm stack is her beloved Cartier watch. She's been a fan of the look for years, having bought herself a two-tone version back in her acting days—since marrying Prince Harry, ...