Sir Paul McCartney is "always interested" in new musical directions.
The former Beatles star - whose debut orchestral work, 'Liverpool Oratorio', was performed in 1991 - was "excited" when he was asked by choreographer Peter Martins if he would consider writing for ballet production 'Ocean's Kingdom' as it was something he had never done before.
He told The Times: "I said that I hadn't [considered ballet before] but would be excited to think about it because I am always interested in new directions that I haven't worked in before.
"I have done a few orchestral pieces and really enjoyed working with an orchestra."
After being approached for the venture, Paul started to see more ballets and dance performances and found the visits inspirational
"When I started to see more dance and ballet, I was influenced by that and started to write more music that I thought would be good to dance to - specifically, writing expressive music that dancers could get hold of and do something with. It has been a very exciting process."
'Ocean's Kingdom', opened in New York last week.