David Cameron offers his congratulations to Royal couple
THe British Prime Minister said the "whole country will celebrate" the birth of the royal baby as news of the child's arrival spread across the globe.
David Cameron offered his congratulations on Twitter where the worlds of showbiz, politics and sport appeared to share in the Duke and Duchess's delight.
He wrote: "I'm delighted for the Duke and Duchess now their son has been born.
"The whole country will celebrate. They'll make wonderful parents."
Meanwhile Oliver Hicks, 31, a close friend of Prince William, said he was thrilled to hear the "fantastic" announcement.
The adventurer said he had been hoping for news since completing the first recorded kayak crossing of the North Sea between Britain and Norway, on Friday.
"It's just such fantastic news," he said.
"Presumably it's also much easier that it's a boy. I hope I'll get to see him soon. I can't wait to see all of them."
Archbishop of Canterbury the Most Rev Justin Welby was one of the first to speak of his joy on Twitter.
"Delighted for the Duke and Duchess of Cambridge as they welcome their baby boy. May God bless them all with love, health and happiness," he said.
Labour Leader Ed Miliband added: "Many congratulations to the Duke and Duchess of Cambridge. I wish them and their son all happiness and good health."
Even former Spice Girl Emma Bunton expressed her excitement - echoing a sentiment felt among the hordes gathered outside Buckingham Palace.
"It's a boy!!! Special times ahead for Kate and William," she said.