Woody Allen's secret was that he was going to play a duet with Bess Myerson - Allen on clarinet, Myerson on flute. For the closing credits of the show, host Steve Allen made it a trio by joining them on trumpet.
The duet played by Woody Allen (clarinet) and Bess Myerson (flute), accompanied by Norman Paris and the band, was an arrangement of the first movement of W.A. Mozart's Piano Sonata in C, K.545.