LONDON — Britain’s newborn prince will be named Louis Arthur Charles, the royal household announced Friday.
In a tweet posted on Kensington Palace's account, royal officials added: "The baby will be known as His Royal Highness Prince Louis of Cambridge."
The Duke and Duchess of Cambridge’s third child was born Monday at St. Mary’s Hospital in London weighing 8 pounds, 7 ounces. They already have a boy, Prince George, born in 2013, and a girl, Princess Charlotte, born in 2015.
It follows days of speculation on the choice of name. British betting chain Ladbrokes said James had attracted the most amount of money, with Alexander also seen as potentially being in the running.

A wait for a royal baby's name is not unusual.
While Prince William, who is second in line to the throne, and the former Kate Middleton waited two days to reveal the names of both George and Charlotte, William's father Charles and mother Diana waited a week to announce his name. The then-Princess Elizabeth, now Queen Elizabeth II, kept the world waiting an entire month before revealing the name of her firstborn, Charles.
And as is tradition, the new prince's name has strong family connections.
Lord Louis Mountbatten — an influential figure who was assassinated by IRA militants in 1979 — was his grandfather Prince Charles' beloved great-uncle. Prince Philip, Queen Elizabeth II's husband, also had a grandfather named Louis of Battenberg.
Prince William has four names — William Arthur Philip Louis. "Louis" also features in his older brother's full name: George Alexander Louis.
The newest member of the royal family is fifth in line to the throne, and the queen's sixth great-grandchild.
The young family now lives in London's Kensington Palace, where William and his brother Prince Harry grew up, after residing for several years at their country home in Norfolk, Anmer Hall.
This year is full of momentous occasions for the royals, who will celebrate Harry’s marriage to Meghan Markle on May 19. In November, Prince Charles, the queen’s son and first-in-line to the throne, will celebrate his 70th birthday.
The queen is scheduled to celebrate another royal birth this summer when she becomes a great-grandmother for a seventh time when Prince William's cousin, Zara Tindall, gives birth.
Prince Louis isn't the only newborn Louis in the U.K. A baby Bactrian camel was spotted by keepers at Blackpool Zoo in northwest England just as news the Duchess of Cambridge had gone into labor broke on Monday. Now the prince's name has officially been announced, the zoo has decided the camel should also be called Louis, too.