The Duke of Cambridge said his spaniel Lupo was "coping alright" with the new addition to the family.
Prince William said, "As a lot of people know who have got dogs and are bringing a newborn back, they take a bit of time to adapt, but he's been alright so far."
More top news
Andy Murray has beaten Belgian David Goffin to win the Davis Cup for Great Britain for the first time since 1936
Mercedes' Nico Rosberg has won the season-ending Abu Dhabi Grand Prix, with team-mate Lewis Hamilton coming second
Celebrities and campaigners have joined a huge rally urging world leaders to agree tough measures to curb global warming