Jumpsuits have been given the green light by Royal Ascot's famously strict fashion police - as long as they are worn full-length to the ankle.
Previously banned, the all-in-one garment has been added to the royal enclosure dress code, organisers announced.
But "fashion forward" spectators in the royal enclosure must still wear the mandatory hat, they added.
In the slightly more relaxed grandstand area, headpieces or fascinators can be worn.
Ladies Day at Ascot has historically been a highlight of the social season.
Trouser suits paved the way for the arrival of the jumpsuit, having been given the nod from Ascot's fashionistas in 1971 - as long as jacket and trousers were in matching colours.
Juliet Slot, Commercial Director at Ascot, said: "The inclusion of jumpsuits as part of the Royal Enclosure dress code recognises our customers' fashion-forward taste and reflects our awareness of seasonal trends."
Skirts must be worn below the knee and shoulders must not be bare.
Men must wear a shirt and tie in the grandstand.
Glamour has been known to fall by the wayside at the event in previous years, with spectators in 2016 spotted ditching their heels for flip flops and bare feet on the trackside lawn.