Lizzie accessorised her look with an elegant set of pearls around her neck, black shoes, and her customary black handbag.
The monarch seems to have a penchant for flowers!
A recent video has surfaced of the Queen breaking her own protocol at the Garden Party in order to accept a bouquet from an over-excited guest.
Among the thousands of guests invited to the soiree was Northern Irish blogger and mother-of-two Laura-Ann Barr, who managed to catch the monarch's attention with a delicate bouquet of flowers, Hello! Magazine reports.
The floral arrangement matched the Queen's powder pink ensemble to perfection, with the filler flowers a carbon copy of the ornate design on her hat.
Queen Elizabeth shocked her attendants by stopping to accept the bouquet, something her security detail revealed has never happened before.
The historic moment was captured by Laura-Ann's mother and has since gone viral, with Laura-Ann admitting the experience was "surreal".
WATCH the moment for yourself below!