News In Depth
First royal baby announced by tweet
The way the pregnancy was announced by the Duke and Duchess of Cambridge illustrates the couple's desire to be in control.
Rather than face news of Kate's hospital stay leaking out and generating an array of speculation, St James's Palace took the unusual step of revealing the pregnancy even though Kate is less than 12 weeks pregnant.
Often the royals have found themselves caught out - when the Prince of Wales and the Duchess of Cornwall became engaged, it was a media scoop that broke the story rather than an announcement initiated by Clarence House.
William and Kate's press notice was released at 4.01pm and later added to Clarence House's Twitter feed, making the baby the first future British king or queen to have the announcement of their expected arrival tweeted by a royal household.
But there was no notice on the gates of Buckingham Palace. This is reserved for when the baby is born.
Prime Minister David Cameron was given advance warning, but only just.
"I got a little note, came into a meeting I was having. I found it quite difficult to keep it to myself," he said.
He added that he was told "not in any great advance of anyone else".