Prince Louis Arthur Charles of Cambridge's Official Birth Certificate Revealed

New royal baby Prince Louis Arthur Charles officially has a birth certificate.

Prince William reported for royal parent duty Tuesday, signing the birth certificate of his third child at Kensington Palace, eight days after the little prince was born. The certificate, made public, shows the royal baby's full name and title: His Royal Highness Prince Louis Arthur Charles of Cambridge. Just like his parents and his older siblings, Prince Louis does not have a last name.

And here's #PrinceLouis' birth certificate, signed by William ("Prince of the United Kingdom"). pic.twitter.com/mlEUoRCSZH

— Omid Scobie (@scobie) May 1, 2018

Signed by royal mom and dad Prince William and Kate Middleton, whose full titles are printed on the certificate, their out-of-ordinary jobs are also revealed: Prince of the United Kingdom and Princess of the United Kingdom.

"It has been a great honour to register, and formally welcome the latest addition to the Royal Family, Prince Louis Arthur Charles," Westminster City Council Registrar, Patricia Gordon, said. "This follows a long history of Westminster City Council registering royal births, including Prince Louis' siblings Prince George and Princess Charlotte."

The Duke and Duchess' third child, now fifth in line to the throne, was born at St. Mary's Hospital's Lindo Wing on Monday, April 23, at 11:01 a.m., weighing 8lb., 7oz. His birth was officially announced via the Kensington Palace Twitter account.

Four days after welcoming the little boy into the world, the royal parents announced that they had named their royal bundle of joy Louis Arthur Charles. In comparison, the royal couple's two older children's names were announced two days after their births.

As Brits and the world-alike anxiously awaited the big reveal, many began placing bets on what the little one's name would be, , with a large betting company based in the U.K. called Ladbrokes having reported that Arthur was the top name, per their top bets. Other contenders included James, Thomas, and Henry.

Though some thought the name was ironic given that Louis was also the name 18 kings from across the Channel, it turns out that the name Louis holds a lot of significance in the Royal Family.

William, along with Louis' older brother, Prince George, share the middle name Louis, which is believed to be a tribute to Louis Mountbatten.

Lord Mountbatten, Prince Philip's uncle, played a key role in the relationship between Queen Elizabeth and Prince Philip, William's grandparents (Louis' great-grandparents). He was also closely related to the royal family by way of his great grandmother, Queen Victoria.

At the time of Mountbatten's death in 1979, he was close with a young Prince Charles, who took his death very hard. Princess Diana reportedly knew the impact Mountbatten had on Charles, which is said to be what first attracted Charles to her.