Hambro's wife, Barbara, told The New York Times that when Borge had memory lapses in the the joint performances her husband would improvise to kill time until Borge recovered.

Hambro was also, for 16 years, a pianist with New York's WQXR, the radio station of the Times, where he played live weekly broadcasts and chamber music recitals.

In one famous episode, Hambro substituted for a sick pianist in a concert of music by Paul Hindemith which the composer conducted at Town Hall in 1952. Hambro learned the part in 24 hours; the Times quotes Hindemith as telling the audience they had witnessed a "kind of miracle."

Hambro toured worldwide and appeared as a soloist with orchestras including those in Boston, Philadelphia, Chicago and London, collaborating with musicians including Fritz Kreisler, Jascha Heifetz and Isaac Stern and performing under Toscanini, Bernstein, Ormandy and Stokowski.

He also made more than 100 recordings; Bartok's son selected him to record all of the composer's piano music, including the premiere recording of the First Piano Concerto with the Boston Symphony, according to the AP.

Hambro was born in Chicago and played his first recital at age 5. He attended the Juilliard School and in 1946 was awarded a Naumburg Foundation award. He subsequently was designated the pianist of the New York Philharmonic.

In 1970, he joined the faculty of the California Institute of the Arts, where he worked as associate dean for 20 years.