Like all couples, William and Kate, the Duke and Duchess of Cambridge, have had their ups and downs. Here are some key moments in their relationship:
September 2001: William and Kate, both studying art history at St Andrews University in Scotland, meet and become friends as undergraduates.
September 2003: The pair and two other friends move into a cottage together for their final year of university -- in the past year both had been romantically linked to other people.
Christmas 2003: Rumours begin circulating that Kate and William may be a couple.
March 2004: The romance is confirmed when Kate and William are pictured together on the slopes at the Klosters ski resort in Switzerland.
January 2006:The couple are pictured kissing in public for the first time, again at Klosters. William begins his army career at Sandhurst shortly afterwards.
April 14, 2007: William and Kate are confirmed to have split.
June 2007: The couple are seen kissing at an Army party and speculation mounts that they are back together.
July 1, 2007: Kate accompanies William to a concert at Wembley Stadium in London in memory of his mother, Princess Diana.
April 11, 2008: Kate attends William's graduation ceremony at Sandhurst.
November 16, 2010: The couple announce their engagement.
April 29, 2011: William and Kate marry at Westminster Abbey and are named the duke and duchess of Cambridge.
December 3, 2012: Royal spokespeople announce that Kate is expecting her first child after she is taken to hospital with severe morning sickness.
July 22, 2013: Kate gives birth to a baby boy at the Lindo Wing of St Mary's Hospital in London. The announcement of his birth is made at 4:24 pm.
July 23, 2013: The baby prince, third-in-line to the throne, makes his first public appearance when William and Kate carry him out of the hospital and show him to a waiting crowd of world media.
July 24, 2013: The couple announce that the new baby will be named Prince George Alexander Louis of Cambridge.
October 23, 2013: George is christened in the Chapel Royal.
April 2, 2014: The couple take George on his first official overseas trip to New Zealand and Australia.
July 22, 2014: George celebrates his first birthday.
September 8, 2014: Royal officials announce that Kate, again suffering from severe morning sickness, is pregnant for the second time.