Britain's Duchess of Cambridge has been discharged from hospital.

The 30-year-old royal - who announced she was expecting her first child with Prince William on Monday (03.12.12) - has made a full recovery and left King Edward VII Hospital in Marylebone, London, where she was being treated for hyperemesis gravidarum (acute morning sickness), this morning (06.12.12).

A spokesperson for St James's Palace issued a statement reading: ''The Duchess of Cambridge has been discharged from the King Edward VII Hospital and will now head to Kensington Palace for a period of rest.

''Their Royal Highnesses would like to thank the staff at the hospital for the care and treatment the duchess has received.''

The news broke on twitter as ITV footage emerged of a rested-looking Catherine exiting the hospital with a grinning William by her side.

The royal spent four days in hospital being closely monitored after experiencing severe nausea over the weekend and was placed on a drip to restore lost nutrients.

Catherine - also known by her maiden name of Kate Middleton - is around eight weeks pregnant and the couple were forced to make the ''difficult decision'' to announce the pregnancy earlier than they would have liked because of her illness.

She was visited by William, 30, every day and her siblings Pippa and James Middleton also rushed to her bedside yesterday (05.12.12).