Prince Charles looked perplexed when a bystander shouted "congratulations" to him during a visit to York Minster.
Charles appeared to say "Who? Me?" before chuckling as the woman explained the greetings were for the "imminent arrival".
As the Prince walked over to her, he joked, "Do you know something I don't?"
More top news
The book by Cameron comms chief Sir Craig Oliver reveals that Mr Cameron was frustrated with Theresa May's neutrality during referendum.
Cloud and outbreaks of rain will ease away eastwards during the morning, clearing the east coast around midday with sunny spells developing.
Police and emergency services are attending the scene.