Having been away for almost three weeks, the Australian-born Danish royal, 53, re-emerged into public view in the chicest of co-ords. She chose a striped linen-blend jacket by Ralph Lauren with the sleeves scrunched to the elbow for a more casual look.
It was paired with the matching trousers that featured a wide leg and tapered waist. It was accessorised to perfection with 'Asia 70' tan leather sandals by Gianvito Rossi, as well as an array of jewels.
According to Royal Fashion Daily on Instagram, King Frederik's wife sported the 'Large Delphis Gold Hoop Earrings' by Dulong, the 'Marrakech Necklace' by Louise Grønlykke, and the 'Ribbon Diamond Bracelet' by Atelier NOTKIN.
For her beauty look, Mary wore her hair in a straight blow-dry and wore a subtle smoky eye and rosy lip shade.
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The mother-of-four chose this outfit as her 'return to work' look – and it was the perfect choice.
"Queen Mary likes to make a statement with her looks, and with her return to royal duties, she's picked out an outfit that I think acts as a perfect symbol of her as a royal," Josh Osman, HELLO!'s Junior Lifestyle Writer and resident Queen Mary fashion aficionado, says.
"Her Ralph Lauren two-piece suit is a breezy, summer-ready choice. With an unstructured blazer and baggier trouser, it has a cooler, more relaxed feel to it, but it's also got the more 'business-casual' look thanks to the pinstripe design.
Josh is also a fan of Queen Mary's choice in accessories. "Dressing the suit down with a pair of heeled sandals is also another way to balance out the more formal aspects of the look," he says.
"All in all, the outfit gives the impression of a classy, but down-to-earth royal, and is a perfectly appropriate choice for a more low-key, but nevertheless important, outing such as opening a new counselling centre."
Prior to her summer break, the wife of the Danish king joined him at the opening ceremony as Denmark launched their EU presidency at Aarhus City Hall. As always, she was impeccably dressed in the 'Sondrio’ Flowing Cady Jumpsuit' by Max Mara.
The statement designer garment, which featured a crew neckline and wrap-over design, was elevated with Ferragamo heels and the coordinating 'Nimbo Clutch' by From By Malene Birger.
King Frederick's wife joined Queen Rania of Jordan and Prince Albert of Monaco at the opening of the Grand Egyptian Museum in Giza – and looked amazing
Prince Albert, Princess Charlene, and their children, Princess Gabriella and Prince Jacques, attended the inauguration of the Christmas Lights on the Place du Casino