Prince Andrew's younger daughter was a vision in green at a soiree held by amfAR at New York's event space Cirpriani Wall Street. Her block colour dress was cinched in at the waist by a thin silver belt, and she accesorised with a bronze-hued bag and shoes.
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Joining Eugenie in showing support for the Foundation of AIDS research were a host of famous faces. Among them were mother-and-daughter acting team Vanessa Redgrave and Joely Richardson, who were honoured at the party.
The pair were given the Award of Courage, which the organisation gives to those who have made exceptionally important contributions to amfAR and the fight against AIDS.
On presenting duty was Liam Neeson, who was married to Vanessa's daughter Natasha until her death after a skiing accident in 2009.
Others joining Eugenie at the bash included Michelle Rodriguez and newly-engaged singer Kelly Rowland.
Since arriving in New York, the Princess has rapidly become a regular on the city's vibrant social scene.
The British royal, who has been living Stateside since the summer of last year, is said to be enjoying her job as a benefit auctions manager at auction house Paddle8. While Eugenie was only meant to stay for a three-month placement, the granddaughter of the Queen landed a permanent role at Christmas after impressing her bosses.
Based in a stylish apartment in the trendy Meatpacking district, Eugenie is said to be "making the most" of her time in the Big Apple.