Something while you wait: The Royal romance in pictures

Kate Middleton and Prince William on the day of their graduation ceremony at St Andrew's University in 2005. Photo / Getty Images

The Duke and Duchess marked their fourth wedding anniversary at Kensington Palace on April 29 and royal fans were hoping that the arrival of a baby today would make it a double celebration.

William met Kate Middleton at university. When the couple got engaged in October 2010 the announcement was first made on Twitter the following month.

They married at Westminster Abbey on April 29 in 2011, watched by a global television audience of millions.

Their firstborn, Prince George was born two years later on July 22, 2013. The second royal baby is due any day now.

Sources have told the Mail that the Duchess's due date was on 25th April and Kate herself told well-wishers the baby was due "mid to late April".

William and Kate this week thanked the "superfans" camping outside the private Lindo Wing at St Mary's Hospital, Paddington, by sending them a royally-approved breakfast treat.

As we await the arrival of the couple's second child, let's take a look back at the royal romance in a series of photos.

William and Catherine: a royal romance in pictures:

June 23, 2005: Kate Middleton and Prince William on the day of their graduation ceremony at St Andrew's University. Photo / Getty Images

February 10, 2007: Prince William and Kate Middleton cheer on the English team during the RBS Six Nations Championship match between England and Italy at Twickenham. Photo / Getty Images

March 19, 2008: Prince William and Kate Middleton on a skiing holiday in Klosters, Switzerland. Photo / Getty Images

April 11, 2008: Prince William and Kate Middleton arrive at the Central Flying School at RAF Cranwell where Prince William received his RAF wings in a graduation ceremony in Lincolnshire, England. Photo / Getty Images

November 16, 2010: Prince William and Kate Middleton announce their engagement at St James Palace in London, England. Photo / Getty Images

April 29, 2011: The Duke and Duchess of Cambridge on their wedding day in London, England. Photo / Getty Images

April 30, 2011: Prince William and Catherine walk hand in hand from Buckingham Palace the day after their wedding to a waiting helicopter as they head out on their honeymoon. Photo / Getty Images

August 2, 2012: Catherine and Prince William during Day 6 of the London 2012 Olympic Games at Velodrome in London, England. Photo / Getty Images

July 22, 2013: Prince William and Catherine depart The Lindo Wing with their newborn son Prince George at St Mary's Hospital. Photo / Getty Images

August 19, 2013: The Duke and Duchess sit with their son Prince George in the garden of the Middleton family home in Bucklebury, Berkshire with Tilly the retriever, and Lupo, the couple's cocker spaniel. Photo / Getty Images

October 23, 2013: The Duke and Duchess holding their son Prince George ahead of the christening of the three month-old in London, England. Photo / Getty Images

April 16, 2014: Prince William and Catherine look at the friendship bands they were given during a walkabout in Civic Square in Wellington, New Zealand. Photo / AFP

August 2, 2014: Catherine holds Prince George as he and Prince William look on while visiting the Sensational Butterflies exhibition at the Natural History Museum, London. Photo / Getty Images

August 4, 2014: Prince William and Catherine attend a WW1 100 Years Commomoration Ceremony at Le Memorial Interallie in Liege, Belgium. Photo / Getty Images

October 21, 2014: Catherine and Prince William smile at each other during a ceremonial welcome for the President of Singapore at Horse Guards Parade in London. Photo / Getty Images

December 7, 2014: Prince William and Catherine arrive at The Carlyle Hotel, where they stayed during their official visit to New York City. Photo / Getty Images

Royal baby timeline

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