Princess Eugenie shares never-seen-before photos of sister Beatrice

Watch: Princess Beatrice Expecting Her First Child This Autumn

Princess Eugenie has shared two never before seen pictures of her sister Princess Beatrice as she congratulated her on her pregnancy.

Eugenie posted a snap from Beatrice's wedding day to Edoardo Mapelli Mozzi, which was not shared at the time, as well as a relaxed shot of the couple at a waterfall.

The waterfall picture appears to be a selfie taken by Mozzi, and shows both of them in hiking and wet weather gear, with Beatrice's hair pulled back into a ponytail behind her.

Eugenie, who welcomed her own son in February this year, posted the pictures with the comment: "It's World Bee Day!! 🐝🐝 A day to celebrate nature's most badass little friend with their black and yellow stripes.. ⁣

"But our furry little 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."

Read more: Princess Beatrice's baby name: Philip and Sarah early favourites

Beatrice, 32, announced she is expecting her first child in the autumn in a statement via Buckingham Palace on Wednesday.

The princess, who borrowed one of the Queen's dresses to marry Mozzi in a secret ceremony in Windsor in July last year, is already a stepmother to Mozzi's son, who is known as Wolfie.

Mozzi and his former partner Dara Huang share son Christopher Wolf, and he was at his father's wedding to Beatrice last summer.

Beatrice and Mozzi had to delay their wedding from the planned May date because of the coronavirus pandemic, and ended up having a much smaller ceremony in the Royal Chapel of All Saints at Royal Lodge, Windsor, following government guidelines and with the Queen and Prince Philip in attendance.

The royal baby will be a cousin to Eugenie's son August Philip Hawke Brooksbank, who was born in February.

The new baby will be the Queen's 12th great-grandchild by the time he or she arrives, as Prince Harry and Meghan Markle's baby is due in summer.

Beatrice's child will be 11th in line to the throne.

Watch: Princess Beatrice makes history with wedding