In the Lindo Wing of St Mary's Hospital, Paddington, Kate gave birth to a baby boy with the help of Mr Alan Farthing and Mr Marcus Setchell.
Mr Setchell described the future King as a "Wonderful baby. Beautiful baby."
It emerged that the Duke of Cambridge was present throughout the birth of the 8lb 6oz baby boy who arrived at 4:24pm on Monday afternoon. In a short statement, the new father said "We could not be happier."
Dr Setchell and Sophie, Countess of Wessex
Mother and son were said to be doing very well.
Mr Setchell was on hand to look after Kate, 31, when she suffered from hyperemesis gravidarum at the beginning of her pregnancy.
He has previous experience of delivering royal babies. He delivered Sophie, Countess of Wessex's two children, Lady Louise Windsor and James, Viscount Severn. He also cared for Sophie following her ectopic pregnancy in 2001.
Mr Setchell was assisted in delivering the future heir by Mr Farthing at the same hospital where Princes William and Harry were born.
Consultant Mr Farthing, 47, is the former fiancé of murdered television presenter Jill Dando. He took up his role in the royal household in 2008. This is the first royal pregnancy since his appointment.
Mr Setchell retired from the NHS in 2008 but continues to practise privately and in a royal capacity. He plans to retire at the end of the year.
Mr Setchell, who will turn 70 in October, has joked that he might return from retirement to deliver the other babies that the royal couple are believed to be planning.
"Marcus says he will retire after the baby is born but because he knows they are planning more children , he will probably have to take time out of his retirement to deliver those too," a source close to Marcus told the Mirror.
The Lindo Wing at St Mary's hospital
The Lindo Wing, within one of London's NHS-run teaching hospitals, also welcomed Zara Phillips and Peter Phillips into the world. According to the hospital's website, a normal delivery package costs £4,965 for the first 24 hours, rising to £6,420 for the first 24 hours of a Caesarean birth .