Blunt paid tribute to the British royal for organising the sporting event on Sunday, reports femalefirst.co.uk.
While introducing his 2004 number one single at the ceremony at the Queen Elizabeth Olympic Park, he told the crowd: "This is a song for someone very special who organised this event. Prince Harry, I dedicate this song to you."
He then started playing the song, which is written about one of the star's ex-girlfriends. Two days back, James Blunt secretly tied the knot with his fiancee Sofia Wellesley who is the granddaughter of the Duke of Wellington. It was a private ceremony.
Prince Harry turned 30 on September 15th, 2014.