He may only be nine months old.
But Kate Middleton has revealed that Prince Louis has marked a fairly big - and important - milestone.
The Duke and Duchess of Cambridge - known as The Earl and Countess of Strathearn in Scotland - were in Dundee for their first official joint engagement of the year, where they officially opened the new Victoria and Albert Museum.
During their visit, the couple spoke with the crowd outside - where proud mum Kate gave a sweet update on her youngest son.
Photographer Mark Stewart
said on Twitter that Kate told a woman in the crowd that "Louis is a fast crawler" - which may mean it won't be too long until the youngest prince is on his feet.
Prince George is said to have started crawling when he was
eight months old, and taken his first steps at 11-months-old. Princess Charlotte, meanwhile, is
said to have taken her first steps when she was a a year old.
It comes as, just before Christmas, it was revealed that the youngest Cambridge had celebrated
another milestone - one that's fairly important for members of the royal family.
The Duchess of Cambridge visited RAF Akrotiri in Cyprus to meet service personnel who would be away from their families for Christmas.
The Mirror report she spoke to Rhian Davis, who was carrying her 10-week-old daughter, Dorothy, in a sling.
Rhian said:
"She asked whether she was sleeping through the night and she told me that Louis is starting to wave."
