Prince William and Duchess Kate Middleton聽welcomed their third child聽on Monday, April 23, and while that鈥檚 reason enough to celebrate, we just can鈥檛 get over how cute Prince George and Princess Charlotte聽looked as they arrived at the hospital to meet their new baby brother.

Prince William left St. Mary鈥檚 hospital聽shortly after聽Duchess Kate gave聽birth to a son, but not before assuring the crowd he would 鈥渂e back in one minute.鈥 Kensington Palace explained in a tweet that he was off to see his two older kids.

He聽returned a half-hour later, hand-in-hand with聽Prince George and Princess Charlotte.聽As聽they walked from the car to the hospital door, Princess Charlotte聽smiled and greeted聽the crowd gathered outside the Lindo Wing, even turning back as they walked up the steps to give one last聽little wave over her shoulder.

Prince George, 4, wore聽his school uniform 鈥 navy shorts, a navy sweater with red trim, and a聽pale-blue oxford聽shirt 鈥 while Princess Charlotte, 2, looked lovely in a blue-and-white patterned dress and a navy cardigan.

The young royals stayed just long enough to meet their new sibling before heading back to Kensington Palace to await their parents鈥 return.

The new royal baby is now fifth in line for the throne, behind Prince Charles, Prince William, Prince George, and Princess Charlotte.聽Prince Harry, who will wed Meghan Markle in a much-anticipated royal wedding next month, is now sixth in line.

How did you introduce your kids to their new siblings? Let us know @BritandCo!

(photos via Gareth Cattermole/Getty Images +聽Chris Jackson/Getty Images)