Prince Harry came into the world at the private Lindo Wing at 4.20pm, weighing 6lb 14oz, on Saturday September 15 1984.
Harry, now the Duke of Sussex, arrived in the same room at St Mary’s Hospital in Paddington, London, where older brother Prince William was born two years earlier.
The Princess of Wales was in labour for nine hours and the delivery of the baby prince, then third in line to the throne, was said to be uncomplicated.
Charles, who had been at Diana’s side, told the waiting crowd that the arrival had been “much quicker than last time” and his baby son had “pale blue eyes” and hair of “a sort of indeterminate colour”.
Speaking to reporters, he described the baby as “marvellous”, adding when asked if he expected a boy: “No. It doesn’t matter what it was as long as it’s alright… I couldn’t be more delighted.”
The prince had first phoned the Queen, and then Diana’s father Earl Spencer, telling him: “He’s a lovely baby.”
Less than 24 hours later, 23-year-old Diana left hospital as the proud parents showed off their newborn on the steps of the Lindo.
Two-year-old William had been brought in the morning by his father to meet his younger brother.
The newspapers reported how the blond toddler, who was dressed in red shorts, a white shirt with red embroidery, white ankle socks and traditional leather bar shoes, ran down the corridor into Diana’s arms as she called his name.
He was said to be “very, very excited about seeing his new brother”.
One royal aide revealed at the time: “There was a lot of laughter coming from the princess’s bedroom.”
The introduction was judged a success, with William holding baby Harry’s hand as he lay in his cot.
He reportedly spent 20 minutes there, before being taken home by his nanny Barbara Barnes, waving to the crowds as he left like a royal pro.
Harry, whose full name was announced as Prince Henry Charles Albert David of Wales, made his first journey in the back of a blue Daimler home to nearby Kensington Palace.
Hours later, Charles celebrated the birth with an impromptu drinks party from the back of a Land Rover at Smith’s Lawn polo ground in Windsor.
The heir to the throne handed out champagne in plastic cups to polo friends after a match he organised to mark the occasion.
But all was not well behind the scenes in the royal couple’s marriage.
The princess years later told her biographer Andrew Morton when she collaborated with him on the bombshell book Diana: Her True Story that she had known Harry would be a boy, but not told her husband.
“I knew Harry was going to be a boy because I saw it on the scan. Charles always wanted a girl… I knew Harry was a boy and I didn’t tell him,” she said.
Diana claimed Charles’s first comment was, “Oh God, it’s a boy”, followed by “and he’s even got red hair”.
The prince’s joke was the beginning of the end of their marriage, with Diana recalling: “Something inside me closed off.”
The prince’s biographer Jonathan Dimbleby wrote that following Harry’s birth, the couple were living “within the shell of a normal marriage” and lacked “intimacy and mutual understanding”.
Dimbleby said that, in the months that followed Harry’s birth, Diana continued to suffer from mood swings, distress and paranoia, and that the gulf between husband and wife, who went on to separate in 1992, failed to close.