The Queen is set to become the longest-reigning British monarch in history, surpassing the record set by her great-great-grandmother Victoria. On Wednesday 9 September, Queen Elizabeth II will have reigned for 63 years, breaking the record held for over a century by her ancestor of 23,226 days, 16 hours and 23 minutes.

Since her accession to the throne more than six decades ago, Queen Elizabeth has become famous for her pearls, block colours, white gloves and extravagant headwear. She has been declared a fashion icon by many – including former model Agyness Deyn – and has been an inspiration to global fashion designers such as Dolce and Gabbana. We took a look back through Queen Elizabeth's fashion history with some photos of her most iconic hats.

Queen's hats
The Queen sports a black and white hat while attending a service of commemoration to mark the end of combat operations in Iraq, at St Paul's Cathedral in London in 2009 Reuters/Luke MacGregor
Queen's hats
Britain's Queen Elizabeth arrives for the State Opening of Parliament at the Palace of Westminster in London wearing a crown in May 2013 Reuters/Dan Kitwood/POOL
Queen's hats
Queen Elizabeth, wearing a red hat, arrives to greet Qatar's Emir Sheikh Hamad bin Khalifa al-Thani at her residence during his state visit in Windsor near London October 2010 Reuters/Dan Kitwood
Queen's hats
Britain's Queen Elizabeth wearing a purple and pink hat on a visit to Northern Ireland in 2009 Reuters/Cathal McNaughton
Queen's hats
The Queen wearing a bright blue hat with Prince Philip at the Epsom Derby festival in Epsom in June 2012 Reuters/Ben Stansall
Queen's hats
Queen Elizabeth leaves Westminster Abbey in London wearing a white hat after her Commonwealth Day message in March 2007 Reuters//Luke MacGregor
Queen's hats
The Queen wears a bright pink hat during her visit to Newcastle in November 2009 Reuters/Owen Humphreys/Pool
Queen's hats
The Queen wears a bright blue hat as she opens the Sainsbury Laboratory for Plant Sciences in the University of Cambridge in 2011 Reuters/Andrew Winning
Queen's hats
Queen Elizabeth wears a light blue hat as she is greeted on arrival at the Epsom Derby festival in Epsom in 2013 Reuters/Stefan Wermuth
Queen's hats
President Barack Obama looks on as Queen Elizabeth holds her hat while the wind blows during an official arrival ceremony on the Buckingham Palace Terrace stairs in London in 2011 Reuters/Larry Downing
Queen's hats
The Queen holds on to her hat in high winds during her visit to her grandson Prince William at RAF Valley in north Wales in April 2011 Reuters/Christopher Furlong
Queen Elizabeth II Prince William Kate Middleton