What to wear when the King and Queen of England come for a visit? That’s just one of the questions that sends the residents and staff of Downton Abbey into a tizzy in the upcoming film version of the hit PBS series.

Luckily, the film’s costume designer, Anna Mary Scott Robbins, had access to a wealth of gorgeous art deco clothing and jewelry — the film is set in 1927 — some of which had some royal bloodlines of their own.

Credit: Jason Bell/Focus Features

Robbins worked very closely with John Bright from London-based Cosprop, which specializes in historical finery.

Credit: Courtesy of Anna Robbins

“John has some pieces of Queen Mary’s actual wardrobe in his archives that we were able to analyze to look at the construction and detail,” she told EW.

In fact, Geraldine James, who plays the queen in the film, wears a dress made using fabric that was actually worn by the real-life royal.

Her majesty isn’t the only one wearing history on her sleeve: Lady Mary Talbot (Michelle Dockery) and her mother, Cora Crawley (Elizabeth McGovern), wear vintage pieces, adapted and embellished by Robbins and her team for a pivotal ball scene.

“For Mary, we used a French beaded gown from a vintage trader that we painstakingly added beading to in order to make it floor length,” says Robbins.

She accessorized it with a tiara made with Swarovski crystals. (Of course, for Maggie Smith‘s Violet Crawley, crystals just wouldn’t do: Her tiara, a 19th-century platinum-and-diamond number from Bentley & Skinner of Piccadilly, contains 16.5 carats of brilliant-cut diamonds.)

As for mama Crawley, the gown Robbins found at a vintage shop in Paris was originally a very un-Cora turquoise. Robbins had it dyed to a lilac mauve before adding two-tone chiffon from London’s Joel & Son Fabrics for its floating sleeves.

“The whole thing came together beautifully,” says Robbins. “Cora wears this shape really, really well.”

In other words: yass, queen.

Downton Abbey opens in theaters on Sept. 20.

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