Catherine gave birth to Prince Louis at 11:01 BST (10:01 UTC) on 23 April 2018 at St Mary’s Hospital in London . The Duke and Duchess of Cambridge's third child is, from birth, a British prince entitled to the style of "Royal Highness" under letters patent issued by Queen Elizabeth II on 31 December 2012, which gave the title and style to all children of Prince William. His name was announced 4 days after his birth on 27 April 2018 as Louis Arthur Charles. He was named after his paternal grandfather's great uncle, Louis Mountbatten, 1st Earl Mountbatten of Burma, and his paternal grandfather, Charles, Prince of Wales.