During the encounter – which was reported by MailOnline – pub-goers couldn’t believe their eyes.
According to the publication a Royal Protection Squad officer checked the toilet at the Phoenix pub in Stockwell, London, before the royal pair could be ushered in.
Pub local Maggie McKinney said: "The little kiddie just trotted in with her mum, went to the toilet and then trotted out. They could not have been in the pub for more than ten minutes.
"They seem very nice, totally normal. Princess Kate was holding her daughter's hand. Princess Charlotte was just any other little girl."