They couldn't wait to meet their new baby brother! Just a few moments after Kate Middleton gave birth to her third royal baby, proud husband and father Prince William left the hospital to go get the newborn's excited older siblings, Prince George and Princess Charlotte.

"George and Charlotte were with the baby for 25 minutes and were very excited to meet their new sibling," an insider said to Us Weekly yesterday. "It’s unlikely they’ll be asleep when William and Kate arrive home. They’ll be up all night, excited about their new brother." The source futher revealed that the family's longtime nanny, Maria, also visited the newborn prince, and then was the one to bring George and Charlotte back home to Kensington Palace.

Kensington Palace shared photos of the young boy and girl with their dad as they arrived at the hospital on their Twitter account. "Prince George and Princess Charlotte arrive at St Mary’s to meet their little brother," the tweet read. They looked so adorable and happy!

Minutes before that, Kensington Palace posted another video of Will leaving the hospital to get into his car while waving to fans. "The Duke of Cambridge departs St Mary’s Hospital to see Prince George and Princess Charlotte at Kensington Palace," the tweet read. He, like his kids, was smiling ear to ear. The palace also confirmed that George and Charlotte "have now returned to Kensington Palace."

The royal family welcomed the fifth member of their brood earlier in the day on Monday, April 23. "Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 1101hrs. The baby weighs 8lbs 7oz. The Duke of Cambridge was present for the birth. Her Royal Highness and her child are both doing well," the statement read. "The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall, Prince Harry, and members of both families have been informed and are delighted with the news." The baby's name has not been released at this time.

George, 4, and Charlotte, 2, were so excited to welcome a little sibling into their family during their mom's pregnancy as well, a source recently told Life & Style. "They rub their mum’s tummy and talk to the new baby. George and Charlotte really are both lovely, normal kids," a family friend told the magazine.

We can't wait to see the first photos of George and Charlotte with their brother!

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