The wedding of Prince Charles to Lady Diana Spencer attracted an estimated global TV audience of 750 million.
The Prince of Wales and the Lady Diana Spencer have ended months of speculation with the announcement they are to be married.
At 11 00 GMT Buckingham Palace made the engagement official.
Lord Maclean, the Lord Chancellor made the following statement at an investiture at the Palace: “It is with greatest pleasure that the Queen and the Duke of Edinburgh announce the betrothal of their beloved son the Prince of Wales to the Lady Diana Spencer, daughter of the Earl Spencer and the Honourable Mrs Shand Kydd.”
Prince Charles proposed to Lady Diana three weeks ago at a private dinner at Buckingham Palace before she went to Australia.
He wanted her to use the trip to think over his proposal but she accepted immediately and he gave her a diamond and sapphire engagement ring.
Delighted and frankly amazed that Diana is prepared to take me on Prince Charles
Despite the intense public interest, they managed to keep their news a secret.
Lady Diana, who is 19, will leave her job as a kindergarten teacher and move out of her flat share in Kensington to live in Clarence House until the marriage.
The couple will then move to the Prince’s house in Highgrove, Gloucestershire.
In a BBC interview, the 32-year-old Prince said he was “delighted and frankly amazed that Diana is prepared to take me on”.
Looking shyly up through her long blond fringe and giggling occasionally, Lady Diana said she too was “delighted and thrilled, blissfully happy”.
Asked how she would cope with a dramatic change to her life she said: “With Prince Charles beside me I cannot go wrong.”
Tributes to the couple were made in both Houses of Parliament. The Prime Minister, Margaret Thatcher, said the news brought “great pleasure” to government and MPs.
They will be married in late July, but exactly when and where has yet to be decided.
Earl Spencer, Lady Diana’s father, said he was also very happy for the couple.
Speaking outside Buckingham Palace with his wife Raine, daughter of novelist Barbara Cartland, he said his daughter had handled the pressures of constant media attention over the last six months very well.
“It will be easier now. She will be under some protection whereas before she had to face the music on her own,” he said.