Prince William visits Kate at the hospital

Britain's Prince William leaves the King Edward VII hospital where his wife Kate, the Duchess of Cambridge, was admitted with a severe form of morning sickness on Dec. 3, 2012. St. James's Palace announced on Monday that Britain's Duchess of Cambridge, formerly known as Kate Middleton, is pregnant and has a severe form of morning sickness for which she is being treated at a London hospital.

Police officers stand guard on Dec. 4, 2012, outside the King Edward VII hospital in central London, where Kate, the Duchess of Cambridge, has been admitted with a severe form of morning sickness.

Prince William, Duke of Cambridge is seen leaving the King Edward VII Hospital on Dec. 3, 2012, in London.

Prince William, Duke of Cambridge, is seen leaving the King Edward VII Hospital on Dec. 3, 2012, in London.

Prince William, Duke of Cambridge, arrives at the King Edward VII Private Hospital on Dec. 4, 2012, in London.

Prince William leaves King Edward VII Hospital in London on Dec. 4, 2012, where his wife, Kate, Duchess of Cambridge, is being treated for acute morning sickness.

Prince William departs the King Edward VII Hospital on Dec. 4, 2012, in London.

Prince William arrives to visit his wife, Kate, Duchess of Cambridge, at King Edward VII Hospital in London on Dec. 5, 2012, where she is receiving treatment for acute morning sickness.

Prince William, Duke of Cambridge, leaves King Edward VII Hospital in London on Dec. 5, 2012, where his wife, Kate, Duchess of Cambridge, is undergoing treatment for acute morning sickness.

157518546.jpg_mask.jpg — Chris Jackson/Getty

A man wearing a Prince William, Duke of Cambridge, mask is escorted away by a police officer from the King Edward VII Private Hospital on Dec. 4, 2012, in London.

157544114.jpg_wills_3.jpg — Stuart Wilson/Getty

Prince William, Duke of Cambridge, departs the King Edward VII Private Hospital on Dec. 4, 2012, in London.