Prince William and Kate celebrate 6th anniversary

LONDON, ENGLAND - APRIL 23:  Prince William, Duke of Cambridge, Catherine, Duchess of Cambridge and Prince Harry cheer on runners as they signal the start of the 2017 Virgin Money London Marathon on April 23, 2017 in London, England.  (Photo by Chris Jackson/Getty Images)

Credit: Chris Jackson

Credit: Chris Jackson

LONDON, ENGLAND - APRIL 23: Prince William, Duke of Cambridge, Catherine, Duchess of Cambridge and Prince Harry cheer on runners as they signal the start of the 2017 Virgin Money London Marathon on April 23, 2017 in London, England. (Photo by Chris Jackson/Getty Images)

The Duke and Duchess of Cambridge are celebrating their sixth anniversary Saturday.

Prince William and Kate Middleton shared a message on Twitter, thanking well-wishers and saying "it's been an amazing six years."

William and Kate now have two children, George and Charlotte, and remain active in public life. They attend many events together, such as the London Marathon on April 23, where they cheered on runners.