Princess Eugenie has shared a sweet series of photos of her baby daughter on Instagram, marking four weeks since the birth of her third child with husband Jack Brooksbank.

Adelaide Brooksbank was born on August 3 — she is the couple’s first daughter, after August, aged five, and three-year-old Ernest.

Princess Eugenie took to social media to celebrate Adelaide’s milestone, with three photos on her Instagram stories: The first shows Eugenie holding the tiny baby with a sunny background.

“4 weeks of you!!,” the photo is captioned.

Adelaide is also pictured with her caring older brothers, August and Ernest, sharing a cuddle with the two boys who are wearing matching outfits.

The brothers are also pictured giving their sister a sweet kiss on her cheeks in a third photo.

“Happy days with my babies,” Eugenie captioned the photo.

Little Adelaide was born in a hospital in Lisbon, Portugal, weighing 6lb 9oz (2.98kg).

She is currently 15th in line to the British throne, and is believed to have been named after either Queen Adelaide, who was the wife of King William IV, or Maria Adelaide of Portugal.

Her name was revealed by her mother Eugenie in an Instagram post two weeks after her birth, which includes a tribute to the late Queen Elizabeth.

“Two weeks ago today we welcomed our girl to the world. And since then we’ve had the most special, cosy and love-filled time,” Eugenie captioned the post.

“We are so happy to share Adelaide Elizabeth Annina Brooksbank.

“Named after three people we love and admire past and present, including her great-grandmother who we hold close in our hearts.

“Her name is part of English and Portuguese history, two places we love and call home.

“Augie and Ernie are already the best big brothers.”

Princess Eugenie and her family are believed to split their time between Portugal, where husband Jack works, and Ivy Cottage on the grounds of Kensington Palace when in the UK.

Get the latest news from thewest.com.au in your inbox.

Sign up for our emails