David Cameron was the first of several politicians who led the flurry of congratulations to the first-time parents Prince William and Kate Middleton, who welcomed a baby boy at 4:24pm on Monday.
"I'm delighted for the Duke and Duchess now their son has been born. The whole country will celebrate. They'll make wonderful parents," tweeted David as soon as he was told the joyous news.
The Prime Minister of the UK gave an official statement on the steps of 10 Downing Street, calling the birth of Baby Cambridge a "wonderful moment for a warm and loving couple".
David spoke on behalf of the public, saying that tonight, "a proud nation is celebrating with a very proud couple."
The leading politician then went on to commend the British royal family on their years of "incredible service" and harked back on the royal milestones over the past few "remarkable" years, taking special note of Prince William and Kate's wedding in 2011, followed by the Queen's Jubilee and now the birth of the third in line to the throne.
A stream of good wishes soon followed, with his counterpart in the US, President Barack Obama, and his wife Michelle sending their congratulations.
"President Obama: Michelle and I are so pleased to congratulate Duke and Duchess on joyous occasion of birth of their first child," posted Sky News.
Hillary Clinton sent her greetings from abroad too, tweeting, "Congratulations from across the pond to the Duke and Duchess! Wishing you the best of luck and a bit of advice: It Takes a (Royal) Village!"
Deputy Prime Minister of the UK Nick Clegg followed suit, posting, "Congratulations to The Duke and Duchess of Cambridge. Good news to make the whole country smile."
"Congratulations to the Duke and Duchess of Cambridge on their new arrival," shared Boris Johnson, Mayor of London, while Ed Miliband posted, "Many congratulations to the Duke and Duchess of Cambridge. I wish them and their son all happiness and good health."
Kate and William: top 15 royal baby names
Kate Middleton labour: William's support and the change in royal protocol
Kate Middleton labour: Ten facts about the royal birth
The Queen arrives at Buckingham Palace as baby crowds gather
Bulletin announcing royal baby's arrival displayed at Buckingham Palace
Palace announces change of plan for royal baby announcement
William called the Queen to break the royal baby news
Kate Middleton and Prince William's number one fan celebrates outside hospital
Euphoric well-wishers celebrate the arrival of Britain's new Prince
HELLO! Online readers congratulate William and Kate