Princess Eugenie and sister Princess Beatrice.Photo: Princess Eugenie/Instagram

Princess Eugenie

The royal mom, whowelcomed her own first childwith Jack Brooksbank in February, posted a special congratulatory message toPrincess Beatriceon Instagramon Thursday. Marking World Bee Day, Eugenie, 31, couldn’t help but reference her own sister, who is also nicknamed Bea.

“It’s World Bee Day!! 🐝🐝 A day to celebrate nature’s most badass little friend with their black and yellow stripes. But our furry friends have to share today with my big sis Bea (🐝) who’s got a little one on the way. Beabea and Edo huge congratulations on your news – can’t wait to meet the little one.”

Alongside the message, Eugenie posted a never-seen-before picture from the couple’s special day. Standing in front of a flower bed, the couple is holding hands and beaming.

In addition to the romantic photo, the youngest daughter ofSarah FergusonandPrince Andrewposted a more casual picture of her sister and Edo too. Looking rainsoaked, a second picture shows the couple cuddled up with a picturesque waterfall in the background.

Princess Beatrice and Princess Eugenie.

LONDON, ENGLAND - JULY 01: Princess Beatrice of York (L) and Princess Eugenie of York attend The Serpentine Gallery Summer Party co-hosted by Brioni at The Serpentine Gallery on July 1, 2014 in London, England. (Photo by David M. Benett/Getty Images for The Serpentine)

Can’t get enough ofPEOPLE’s Royals coverage?Sign up for our free Royals newsletterto get the latest updates onKate Middleton,Meghan Markleand more!

Princess Beatrice and Edoardo Mapelli Mozzi.Benjamin Wheeler/PA Wire

Princess Beatrice wedding

source: people.com