Aunt Pippa has arrived!
Kate’s younger sister, who is reportedly expecting her first child with husband James Matthews, arrived at Kensington Palace to meet her new nephew on Tuesday — just one day after the prince was born.
Wearing a pink coat and an oversized pink turtleneck, Pippa was one of the first family members to meet the newborn. Uncle Prince Harry and Meghan Markle, who live just a stone’s throw away from the royal family of five, are also expected to be one of the first to meet the new prince.
Prince Charles, who joked about how he’s going to have trouble keeping up with all his grandchildren, will reportedly visit his new grandson after he returns from Anzac Day commemorations in France on Wednesday.
Queen Elizabeth celebrated the latest addition to her family with a quick horseback ride through the grounds of Windsor Castle, where she is staying with husband Prince Philip, who is still recovering from hip surgery.
RELATED VIDEO: Pippa Middleton Is Reportedly Pregnant with Her First Child — at the Same Time as Sister Kate!
Pippa’s pregnancy news broke on Saturday, just days before Kate was admitted to St. Mary’s Hospital in London in the early stages of labor with her third child on Monday morning.
Pippa and her husband tied the knot last year on May 20 at St. Mark’s Church in Englefield. Prince George and Princess Charlotte were an adorable pageboy and little bridesmaid in her wedding party. Now, she has a new little nephew to share in her milestones.
As a mother of three, Kate has plenty of sage advice (and designer maternity clothes!) to pass on to her younger sister.
A source previously told PEOPLE that Middleton and Matthews are looking forward to settling down and “having children and leading a quiet life.”
The name of Will and Kate’s baby boy will be announced in due course, the palace said. Albert and Arthur are tied as the most popular names for a boy – at 5-1 and 9-1, respectively, according to British oddsmakers.
- Can’t get enough of PEOPLE’s Royals coverage? Sign up for our newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!
The royal baby remains fifth in line of succession after Prince Charles, Prince William, Prince George and Princess Charlotte.