The happy couple were all smiles as they sat in the front row at the lavish fashion show, held at the Palazzo Pitti in Florence, Italy.
Dunst, 35, rocked a burnt umber button-down blouse with a black collar, along with a vibrant, colorful patterned skirt. Plemons, 29, wore a brown suit with a pale orange dress shirt sans tie.
Dunst was recently in Cannes, France, for the premiere of her new drama The Beguiled. The actress got emotional on the red carpet, where she was joined by co-star Elle Fanning and director Sofia Coppola.
News of Dunst's engagement to her Fargo co-star broke in January, and the couple were spotted for the first time after getting engaged at the 2017 Film Independent Spirit Awards in Santa Monica, California in late February.