Sir Paul McCartney was joined by his glamorous fiancée Nancy Shevell and a host of A-list celebrities on Thursday night at the world premiere of his first-ever ballet score in New York.

The former Beatles star, 69, confessed he was “quietly confident and nervous” before the debut of Ocean’s Kingdom, which was performed by the New York City Ballet at Manhattan’s Lincoln Centre.

Sir Paul seemed in high spirits as he took to the red carpet and posed for photographs with Nancy Shevell – whom he is to soon marry.

The American businesswoman wore a shimmering black backless sequin dress while the youthful-looking music legend looked dapper sporting a black suit and tie.

They were joined by a host of A-listers including his daughter Stella McCartney – who worked on the costumes for the production – Sex and the City star Sarah Jessica Parker and actresses Naomi Watts and Liv Tyler.

Sir Paul, who has worked on other classical works including his Liverpool Oratorio, took on the project after meeting the NYCB’s ballet master in chief, Peter Martins, last year at the School of American Ballet’s winter gala.

He revealed he saw it as “a challenge” as he had never before written an original orchestral score for dance.

The music legend said of his involvement: “Trying to write something that expressed an emotion was very interesting – so you have fear, love, anger, sadness to play with, and I found that very interesting and challenging but great – I’m really glad I accepted.”

He added: “I enjoy writing music full stop, so whether it’s an orchestra or rock, I immerse myself in it.

“I’m a very enthusiastic person so I enjoyed the process – I didn’t really find it too difficult. What was interesting was writing music that meant something expressively rather than just writing a song.”

The singer songwriter also revealed he tried out his own ballet moves as part of his research as he knew little about the classical world of dance

He said: “I’d seen the great traditional ballets like Swan Lake and The Nutcracker, but I had a very limited knowledge of ballet.

“But since this project I’ve obviously started to take notice – I went to see Giselle recently in London and was bowled over by the sheer athleticism of the dancers.

“The next day I tried to do one of the steps and failed dismally, which gave me a new admiration for the dancers.”

Sir Paul’s first orchestral work, a collaboration with Carl Davis called Liverpool Oratorio, was first heard in 1991. Since then he has released Standing Stone, Working Classical and Ecce Cor Meum.

He will release an album of his music from Ocean’s Kingdom next month, recorded with the London Classical Orchestra.