Michael Feinstein says Americans have lost their appreciation of the arts. So the singer, pianist and purveyor of The Great American Songbook is eagerly anticipating his capital concert next month as part of the London Festival of Cabaret. Feinstein — who was a close friend of Frank Sinatra — learned to play the piano by ear as a child and trained with Ira Gershwin in Los Angeles from the age of 20, serving as archivist for the lyricist in his final years.

Since then, he has forged a reputation by performing the classic melodies, including Broadway hits from the 1920s and the songs of George and Ira Gershwin. Nominated for five Grammys and two Emmys, the 57-year-old has also penned a tribute to the brothers, The Gershwins and Me: A Personal History in Twelve Songs.

“That era is timeless, like Shakespeare,” reflects Feinstein down the line from New York. “It brings in the emotion, power and passion of an era to a contemporary audience that you just don’t get any more.

“The Gershwin brothers were geniuses in their own time. George changed the face of music by incorporating jazz and rhythm and blues elements. No one had ever done what he did. That’s why the music has such a seductive quality. It just feeds into the soul in a certain way. George was a true genius — music came to him as though it was divine speak.” To Feinstein, contemporary music lacks the feel and impact “of songs from the classic time”. And with the rise of pop princesses from Madonna to Lady Gaga, he believes “the arts in America are devalued — which is unfortunate”.

With Sinatra, “we bonded over a shared love of music. I didn’t care about his tabloid life, about his anger fits or his relationship with Ava Gardner. I was interested in him as a musician. I knew him from social events at his house.

“He was a different man to the one in public. He opened up to me in a different way. He had a love and great knowledge of classical music. He had sophisticated taste.

“[Sinatra] always knew that the people who made the music wrote great songs that made him famous — they put him on the map. Without those songs he would never have been iconic, so he always paid them back. After a performance he always recognised the musicians.”

Feinstein says he has “always been so passionate about music. It’s important to every aspect of life, whether you know it or not. It has built bridges for me my entire life.

“I’ve been lucky enough to make a living doing what I love. But if I was playing the piano in a bar lounge, I would be just as happy. Many people have music in their lives and it is just as important to them as it is to me — physically, emotionally and spiritually.” He will never have to take the piano bar route, being part owner of a New York nightclub and with his own record label, Feinery. He has been invited to perform at the White House and Buckingham Palace.

His fourth Grammy nomination was for Michael Feinstein with the Israel Philharmonic Orchestra in 2003, his first recording with a symphony orchestra. He says that working with the IPO “was a great highlight of my career. I’ve had the opportunity to play with some of the greatest orchestras in the world — and [the Israelis] are world-class musicians. They have no snobbishness. They would play Frank Loesser as seriously as they play Beethoven.”

He adds: “It was illuminating and marvellous to play with the Israelis. Wherever there is unrest in the world, people turn to music to feel better. The music experience opens up questions and ways to make a change.”

Feinstein’s cultural Judaism is an integral element of his performances. “I was raised a Jew and this is very important to me,” stresses the Ohio-born artist, whose father was an amateur singer and whose mother was a tapdancer. “Most popular American songs were by great Jewish songwriters. Jewish culture is extremely important and I use Yiddish terms on stage from time to time. Yiddish is very expressive and other words cannot always have the same power.

“When I play for an upper-crust Wasp audience, I always show off my Jewish heritage. The music and performance builds bridges.”

He is “very much looking forward to performing for the British audience” with friends Elaine Paige and Julian Ovenden. “The British audience are wonderful,” he enthuses. “They still very much respect the theatre and concerts. They still have an appreciation for the arts.”

The duets “will be great fun”, he promises and, of course, the audience should “expect some Gershwin songs. People expect me to play them and I’m happy to oblige.”

Now dividing his time between homes in New York, LA and Indiana — where he is artistic director of the Centre for the Performing Arts — how long will he continue performing?

“Performing still feels right at this time,” he replies. “But nothing is forever. I’m an instinctive person and when I feel that something is not good in my soul, I will stop. As long as I should be doing it, I will.”

Michael Feinstein and Friends is at the Palace Theatre, London, on November 4