The future and current Queens of Denmark perfectly matched the national flag as they celebrated its 800th anniversary.
The Danish royal, 47, looked a picture of elegance as she teamed a bold beige headdress with her striking red, long-sleeved dress.
Australian born mary also wore her brown locks back in a sleek side bun, while also donning a beautiful pair of diamond earrings.
Queen Margrethe II also wore red for the occasion, wearing a sophisticated red blazer on top of her red, black and white patterned dress.
Queen Margrethe II of Denmark arrived in true regal fashion, on board her grand ship, the Dannebrog.
Mary shares four children with husband Prince Frederik; Prince Christian, 13, Princess Josephine, 12, and eight-year-old twins Princess Isabella and Prince Vincent.