April 23, 2018, 11:48 a.m.: Here they are! Prince George and Princess Charlotte have arrived with their dad to meet the newest member of the royal family.
Prince George is in his school uniform, while Princess Charlotte is in a blue dress (in honor of her new baby brother, perhaps?) and a navy cardigan.
April 23, 2018, 11:26 a.m.: The newest member of the royal family was just born a few hours ago, and he's already about to get a visit from his older brother and sister.
Shortly after welcoming the new royal who was born at 11:01 a.m. GMT, Prince William left the Lindo Wing to pick up Prince George, 4, and Princess Charlotte, 2, so they can visit St. Mary's Hospital to meet their new sibling, whose name has yet to be announced.
Prince William said, "I'll be back in a minute," to the press waiting outside the hospital.
Kensington Palace announced the arrival of the new royal this morning on Twitter.
The tradition of the older sibling meeting their new brother or sister at the hospital goes all the way back to when Prince William was a young tot. See a throwback of him, below, arriving at the hospital to meet Prince Harry.