Princess Eugenie, 28, and Princess Beatrice, 29, are currently visiting New York.
The royal pair were spotted last night attending a NEXUS meeting at the UN headquarters.
Looking perfectly presented and polished, the twosome beamed and laughed at one another, as Beatrice playfully posed to cameras on the escalators.
Posing aide, the York sisters were dressed to impress, as they discussed humanitarian issues at the UN.
Princess Eugenie wore a familiar dress, the same ensemble she wore to Royal Ascot 2018.
The cream-based dress, by her favourite designer Erdem Moralioglu, was emblazoned with summery floral prints.
The prints appeared to be of wildflowers, possibly a nod to the English countryside.
Taking style inspiration from eras gone by, and her grandmother the Queen in particular, the dress featured a high, ruffled neckline.
Coming to just above her knee, the dress also featured long sleeves, which were cinched in at the wrist and puffed out around her arms.
The dress was reminiscent of the styles the Queen used to wear in the 1950’s, often spotted in high-neck and floral-print designs.
On her feet she wore a simple pair of black pointed-toe court shoes, with silver studding detail around the edge.
A fan of bold colours and prints, Eugenie could incorporate her signature style into her wedding dress.
The bride-to-be is getting married this October to wine merchant and tequila ambassador Jack Brookbank.
Contrasting Eugenie’s summery, floral attire, Princess Beatrice looked more formal in tailored navy blue jersey dress.
Hanging just below her knees, the dress featured a crew-cut neckline, with long sleeves despite the scorching New York heat.
A tie at the waist gave the stretchy dress some more shape, with button detailing also featuring on the lapels.
In her hand, she carried a tiny floral purse, positioned below her UN ID card.
Her strappy black shoes added a more summery element to the dark ensemble, with double strap and buckle detailing.
In another contrast to Eugenie, who wore her red hair down, Beatrice took inspiration from her cousin-in-law Meghan Markle, wearing her long hair scraped back in a low bun.
Meghan was at the polo yesterday wearing her hair in the same style, snapped sharing a passionate kiss with her husband Prince Harry.