Kate Middleton and Prince William welcomed the duchess' parents, Carol and Michael Middleton, as well as sister Pippa for the first family greeting with the royal newborn on Sunday morning.
According to the BBC, Princess Charlotte Elizabeth Diana was born on Saturday at St. Mary's Hospital in London, weighing in at 8 pounds, 3 ounces. She is fourth in line to the throne.
The Middletons beat fellow grandparents Prince Charles and wife Camilla to Kensington Palace for the celebration.
Emilia Jardine-Paterson, a friend of the duchess and godmother to Prince George, was also said to be in attendance.
Queen Elizabeth, 89, is expected to meet her great-grandchild when the duke and duchess decamp to Anmer Hall on the Queen's Sandringham estate in Norfolk this week. Prince Harry, the princess' uncle, just missed her arrival, as he had to return to Australia, where he is stationed with the army.
"She is absolutely beautiful," he said in a statement released by Kensington Palace. "I can't wait to meet her."
"The duke and duchess are hugely grateful for the messages of congratulations they have received from people all over the world. It means a great deal to them that so many people have celebrated the arrival of their new daughter," the statement said further.
The princess' big brother, Prince George, will turn 2 this upcoming July.
Many British newspapers dedicated their Sunday covers to the new princess, while many so-called mommy bloggers on both sides of the pond were shocked at how good Middleton looked just hours after giving birth.