Kate Middleton and Prince William Name Royal Baby No. 3!

The couple welcomed their third child on Monday but didn't announce the name until Friday.

Prince George, Princess Charlotte, and Prince Louis!

Kate Middleton and husband Prince William welcomed royal baby no. 3 on Monday, but chose not to announce the little boy's name until Friday. 

In a statement from Kensington Palace, the couple revealed, "The Duke and Duchess of Cambridge are delighted to announce that they have named their son Louis Arthur Charles. The baby will be known as His Royal Highness Prince Louis of Cambridge."

The Duke and Duchess of Cambridge's newest addition was born at 11:01 a.m. local time and several hours later the traditional ceremonial easel was placed in front of Buckingham Palace, which did not reveal the boy's name. There have been lots of speculation over the past few days about what they would name their son, with Albert, Thomas, and Henry being tossed around as top predictions. 

Kensington Palace announced the baby's birth in a statement, saying, "Her Royal Highness and her child are both doing well. The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall, Prince Harry and members of both families have been informed and are delighted with the news."

Baby Louis joins 4-year-old brother Prince George and 2-year-old sister Princess Charlotte. His birth makes history for Princess Charlotte, who will be the first female heir not to be superseded by her younger male heir in the line of succession. Charlotte remains fourth in line to the throne while her new brother is now fifth. 

Kate, 36, attended her last official event before her maternity leave in late March, though William, 35, has continued on in her absence. The father of three attended Queen Elizabeth's birthday celebration over the weekend in addition to a series of events for the Commonwealth Heads of Government Meeting last week.

Prior to the baby's arrival, new unconfirmed reports came out that Kate's younger sister, Pippa Middleton, is pregnant with her first child.

But the next major event for the royal family will be Prince Harry and Meghan Markle's May 19 royal Wwedding. It's unknown whether Kate or the new baby will attend the couple's highly anticipated nuptials, though William, George and Charlotte will all play a big part in the ceremony.