A photograph was tweeted by Kensington Palace at 9pm on Saturday evening (6 June), marking the first time the little princess and her big brother Prince George, 23 months, have been seen together.
The image was taken by proud mum Kate Middleton in mid-May.
Kensington Palace had earlier teased the image by saying: "We'll be posting a very special photo of Prince George & his little sister Princess Charlotte late tonight. Can't wait to share it with you!"
Princess Charlotte Elizabeth Diana was born at St. Mary's Hospital on 2 May. Before this evening, the only photos we had seen of her came when Kate and William left the hospital with her that day.
She is fourth in line to the throne.
The decision to release informal family pictures of Charlotte echoes the images released of Prince George shortly after his birth. Those pictures were taken by Kate's father Michael at the Middleton family home in Berkshire.
Known as HRH Princess Charlotte of Cambridge, the baby will be christened on Sunday, 5 July at St Mary Magdalene Church in Sandringham. She will be baptised by the Archbishop of Cambridge.
No godparents have been named yet but Prince Harry, Princess Beatrice and Pippa Middleton are all rumoured to be contenders.
William, Kate, George and Charlotte relocated from Kensington Palace to Anmer Hall in Norfolk shortly after Charlotte's birth. The mansion was a gift from The Queen for their wedding and is located within the Sandringham estate.
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