The duo record the song together inside of an intimate and darkly lit studio in the clip released on Friday.
Gaga and Bennett are joined by a full jazz band. The pop star gives the music legend notes on his lyrics sheet and gives Bennett a hug.
"Night and day, you are the one/ Only you beneath the moon and under the sun/ Whether near to me or far/ It's no matter darling where you are/ I think of you/ Night and day," Bennett sings.
"Night and Day" appears on Gaga and Bennett's newly released album Love for Sale and can be streamed through Spotify, Apple Music, Amazon Music, YouTube Music and Pandora.
Bennett, who is 95 and has Alzheimer's disease, announced in August that he was retiring from live performances.
Gaga and Bennett will be featured in three upcoming television specials that will air on CBS, MTV and Paramount+. The specials include concert One Last Time: An Evening with Lady Gaga & Tony Bennett, a new installment of MTV Unplugged and documentary The Lady and the Legend.