Photo: Getty

Zac Posen has shared a never-before-seen photo of Princess Eugenie in her striking second wedding dress on social media in celebration of the royal’s 29th birthday over the weekend.

Eugenie’s romantic blush gown was custom-made by Posen, and the princess recently revealed that it was based on the outfits Grace Kelly wore in 1955 film To Catch a Thief.

Eugenie married Jack Brooksbank at St George’s Chapel in Windsor in October last year.

Related articles: The Queen Just Shared Her First Instagram Post 

The Instagram picture features Posen down on one knee while holding the gown. The accompanying caption described Eugenie as “a young lady who possessed natural elegance, a heart of gold and sophisticated humour”.

“Every now and then you meet somebody who just knocks your socks off,” he wrote in the heartfelt message. “This last year I got to know a young lady who possessed natural elegance, a heart of gold and sophisticated humour.

“My studio and I had the honour (and the best time) collaborating with her on her special gown. Best of all she is dedicated to using her privilege to help our world and its people with her project @the_anti_slavery_collective. Happy Birthday!”

Photo: Royal Collection Trust

Eugenie and Jack Brooksbank’s wedding outfits have gone on display at Windsor Castle, with Eugenie recording part of an audio guide for visitors, explaining previously unknown details about her two wedding dresses. The gown that she wore for her wedding ceremony was designed by Peter Pilotto and Christopher de Vos of Pete Pilotto, and featured a low back to show off her scoliosis scar.

Related article: Breaking News: Prince Charles Has A Cracking Bod 

Photo: Getty

The royal also described Posen as “such a cool, fun, brilliant designer and friend” in the audio guide.

Meanwhile, Eugenie and Jack carried out their first royal engagement as a married couple.

Along with Prince Andrew, the couple visited the Royal National Orthopaedic Hospital in London to open the new Stanmore Building. The princess and her father unveiled a plaque together, before she and Jack toured the hospital.

Related article: Every Time Kate Middleton And Princess Charlotte Were Style Twins 

This article originally appeared in Harper’s BAZAAR UK