She may be a month behind her big brother, but Princess Charlotte has started walking, as a first birthday picture taken by the Duchess of Cambridge shows.
The Princess, who is one today, is pictured standing on her own two feet for the first time in the garden at Anmer Hall, the Duke and Duchess of Cambridge's Norfolk home.
And the smile on her face suggests she is mightily proud of herself as she pushes a wooden trolley full of building bricks across the lawn.
Earlier this month the Duchess said her daughter had started "cruising" around the furniture at home, but she seems to have progressed even further since then.
Prince George took his first steps at the age of 11 months, and will no doubt be looking forward to chasing his sister around the house once she learns to run.
Four pictures of the Princess, all taken by the Duchess of Cambridge, were published on Kensington Palace's official Twitter feed yesterday, with the Duke and Duchess saying: "We hope that everyone enjoys these lovely photos as much as we do."
They were all taken over the past week at Anmer Hall, and show the Princess in her pink and white bedroom; sitting on a child-sized rattan chair and playing on the floor with a copy of Wheels On The Bus, a sound and action book by David Ellwand.
The close-up pictures of Charlotte show that she is starting to show a distinct resemblance to Prince George, suggesting she takes after her father.
The Duchess, who uses a Canon EOS 5D MkII, has taken on the role of official family photographer since her marriage to the Duke five years ago. She also posted her own pictures of Princess Charlotte on social media last year, as well as pictures of Prince George kissing his sister when she was newborn.
She has once again shown she has an eye for a picture, with the added benefit of being able to get the best out of her children as a mother.
As with Prince George at the same age, however, Princess Charlotte's smile remains elusive. While Prince George famously adopted a sulky pout whenever he was photographed, Princess Charlotte puts on a rather serene expression for her mother in the three pictures taken indoors.
The photographs appear to have been taken on different days, as the Princess is wearing two different outfits - a blue dress with a white cardigan, and an all-pink dress and cardigan set. Her hair has also grown long enough that she needs clips and bows to pin it back.
A week ago, to celebrate the Queen's 90th birthday, she was seen posing on Her Majesty's knee in a photograph taken by Annie Leibovitz.
The Duke and Duchess are expected to celebrate Princess Charlotte's birthday with a small party at Anmer Hall with their friends who have children of a similar age.
The Princess is then likely to be taken to see the Queen - who is currently residing at Windsor Castle - next time the family are in London.
A spokesman for the Duke and Duchess said: "The Duke and Duchess are very happy to be able to share these important family moments."