Prince William and Kate Middleton have named the royal heir George Alexander Louis, Kensington Palace announced in a statement today.
"The Duke and Duchess of Cambridge are delighted to announce that they have named their son George Alexander Louis," the palace said.
The baby's official title is His Royal Highness Prince George of Cambridge.
The baby boy was born Monday at 4:24 p.m. London time. He weighed 8 pounds, 6 ounces, according to an official announcement from Kensington Palace four hours after the birth.
The newborn's names would be announced "in due course," the statement said.
When the new family departed from St. Mary's Hospital's Lindo Wing Tuesday, the world got its first glimpse of the little prince who came out in his mother's arms. The day-old baby was swaddled in a white blanket and poked his hand out, as if to greet the world.
"We're still working on a name, so we'll have that as soon as we can," a beaming William told the throngs of people gathered outside. "It's the first time we've seen him, really, so we're having a proper chance to catch up."
"It's very emotional," Kate said. "It's such a special time. I think any parent will know what this feeling feels like."
While British royalty don't typically use a surname -- although they may use "Wales" or "Mountbatten-Windsor" when a surname is required -- they often have several middle names.
Prince William's full name is William Arthur Philip Louis.
Oddsmakers had been taking bets on several aspects of the birth, including the heir's birth date and weight, hair color and possible name.
As of Monday night, bettors with Ladbrokes, a bookmaker in England, had put George and James as the most likely names, with 3-to-1 and 4-to-1 odds, respectively. Alexander rounded out the top three with 7-to-1 odds.
More traditional names with longer odds were Louis, Henry, Albert and Arthur. Bettors thought the highly non-traditional Elvis, Jahmene, Rylan, Psy and North were the most unlikely choices, each with odds of 500-to-1.
It has often taken some time for royal babies' names to be announced.
When William was born on June 21, 1982, his parents didn't reveal his name until one week later.
His father, Prince Charles, was a month old before his name was made public. His niece, Princess Beatrice of York, was about two weeks old before her name was announced.
William's brother, Harry, was an exception. His name was announced on the day he was born.