Says My Heart 1938 - Frank Loesser-Burton Lane

Red Norvo's Orchestra modulates to Ab for Mildred Baily's vocal.
https://m.youtube.com/watch?v=MTOyp505I5M

Billie sings it in F
https://m.youtube.com/watch?v=ZcTVWOtppuA

Ozzie's orchestra modulates from C to Eb for Harriet Hilliard's (Nelson) vocal (yup, Ozzie & Harriet)
https://m.youtube.com/watch?v=wdgeoROenEw

It was Harriet Hilliard Nelson who introduced this popular tune in the now-rarely-seen Paramount musical “Cocoanut Grove,” which starred not husband Ozzie, but Fred MacMurray as Harriet’s leading man. The featured band was Harry Owens and his Royal Hawaiians.

)BOB