Be still our Downton Abbey-loving hearts! Our tickers are beating a mile a minute after receiving new details about the tiara that Lady Mary Crawley (Michelle Dockery) wears for her—spoiler alert!—wedding to on-and-off beau Matthew Crawley (Dan Stevens) in Season 3 of the primetime soap opera, which already premiered in the U.K. (it lands stateside this January!). To create Crawley's bridal look, the show's costume designers collaborated with Britain-based antique jeweler Bentley & Skinner. Together, they created the Georgian tiara for Lady Mary's stroll down the aisle. The stunning topper features 45 carats of pavé-set old-cut diamonds set in yellow gold and silver, and is worth $200,000. It can also be transformed into a brooch and headband. We can't wait to see the crowning moment!Plus, get to know the rest of the Downton Abbey cast!