A host of US media and celebrities feted Monday's birth of the royal baby while President Barack Obama and his wife Michelle hailed the 'special relationship' between the two nations, offering 'all the happiness and blessings parenthood brings'.
Americans were thrilled Monday at news from across the pond that Prince William's wife Catherine had given birth, with President Barack Obama leading a chorus of well wishes.
"Duchess of Cambridge Has Given Birth to a Baby Boy, Palace Says," heralded The New York Times in one of many smartphone alerts from news media that ricocheted around the nation.
Obama and his wife Michelle, the parents of two school-aged daughters, wished William and Catherine "all the happiness and blessings parenthood brings."
"The child enters the world at a time of promise and opportunity for our two nations," the president said in a White House statement.
"Given the special relationship between us, the American people are pleased to join with the people of the United Kingdom as they celebrate the birth of the young prince."
Outside the White House, a group of mothers with children in tow cheered the royal birth.
"She had her baby? I didn't know," one woman told AFP. "It's a boy? How exciting!"
"No, I wanted it to be a girl," another said, but a third woman stated: "Nothing wrong with a boy... Another (royal) boy for the girls to crush on."
Even famously hard-bitten New Yorkers were caught up in the excitement.
"It's just so great. I heard about it on Twitter and then we had the TV on for like an hour in the office," secretary Melissa Klein told AFP.
"Don't ask me why, but it's a big thing for America."
At Tea and Sympathy, a British-themed restaurant in Greenwich Village, union jack bunting went up as soon as it was announced that Kate had gone into labor -- followed by blue "It's a boy" banners once news of the birth came through.
"There was a huge cheer, it was so exciting," restaurant manager Hayley Simmonds, originally from London, told AFP.
"Everyone seems to be ordering afternoon tea today. They want to have something special to celebrate."
News channels like CNN, Fox News and MSNBC broke into their regular programming for live reports from correspondents on the ground in London.
"It's really with a sense of excitement that the crowds are beginning to gather at Buckingham Palace," said one CNN reporter over a live aerial view that in fact showed just a few hundred at the gates.
Fox News, famous for its conservative editorial slant, pointed out that the British royal family enjoys "a higher approval rating" than Barack Obama.
"It establishes once again why Britain is such a great nation," Neil Gardiner, a British expat at the right-wing Heritage Foundation in Washington, told the channel.
Online, gossip websites tested the limits of lese majeste.
"The Duchess of Cambridge has finally given birth to the Cookie Monster that has been growing inside her like a parasite for the better part of a year," the achingly hip Gawker.com said.
"According to Buckingham Palace officials, Kate popped at precisely 4:24 PM GMT," added TMZ.com alongside an online poll asking readers if they thought "the royal heir will lose his hair" like his balding father and grandfather.
Two out of three responded yes.
On Twitter, celebrities fell over each other with congratulatory messages.
"It's a boy! So happy for my cousin Kate and the future King of England!" tweeted talk show host Ellen DeGeneres, recently informed by the New England Genealogical Society that she is indeed a distant relative of the future queen.
Fellow funny lady Joan Rivers quipped: "Congratulations to Kate & William on the birth of their baby boy! So relieved that his name won't include the words Ivy or Apple."
Date created : 2013-07-23