Trumpet: B5, Trombone: G4
Yes, this is main theme from the 1979 film Agatha starring Dustin Hoffman and Vanessa Redgrave, and has since become a jazz standard. This could also be performed by a vocalist and has been recorded by Tony Bennett, Lena Horne, Dianne Reeves, and many others. Definitely a change of pace, and a welcome in a concert.
From the recording: Johnny Mandel Conducts the Music of Mandel, featuring the DIVA Jazz Orchestra.
Standard Big Band (5/4/4/4)
Woodwind 1, 2: Alto Flute/Flute; Woodwind 3: Alto Flute/Flute/Clarinet; Woodwind 4: Flute; Woodwind 5: Bass Clarinet