YouTube comes through from time to time with classic moments in TV history that I've since lost to VCR-tape deterioration. This is one of those moments.
In part one, watch Bette Midler's semi-memorized and well-rehearsed good-bye letter, sung to Johnny Carson on his second-to-last night:
Part two below is a totally improvised duet of "Rainy Day" that Johnny and Bette do: