In a statement issued by Clarence House yesterday (3rd December), it was revealed that the Duchess of Cambridge is suffering from Hyperemesis Gravidarum (morning sickness) and was admitted to King Edward VII hospital in London.
Middleton is thought to be in the early stages of pregnancy - with some reports suggesting she is only eight weeks gone. The Daily Mail has also claimed that the pair had "no plans whatsoever" to announce the pregnancy so early.
A Royal source added to The Sun: "William and Catherine are very happy but understandably nervous given her illness.
“They weren’t expecting to announce this so soon but once it was clear the Duchess had to spend several days in hospital it became clear the news would leak out.”
BBC News has since confirmed that Kate is being treated by gynaecologist Marcus Setchell - who delivered the Countess of Wessex's two children.
According to The Mail, K-Middy has been hooked up to a drip so she doesn't become dehydrated and is responding well treatment, with "no cause for alarm" necessary.
A anxious Prince William was seen visiting Kate at hospital yesterday, and is thought to have left his wife's bedside at 8.12pm - offering well-wishes a smile before leaving in a car.
The likes of Cheryl Cole, Olly Murs and the Kardashian sisters have all offered their congratulations to the Royal couple, with Prime Minister David Cameron stating Wills and Kate "will make wonderful parents."
Their baby will replacePrince Harry as the third in line to the throne.