"Mama" Cass Elliott had a beautiful voice, and would have been one of the most sought-after vocalists for decades to come had she not died (at age 33) in 1974.
"Dream a Little Dream of Me" is often credited as a Cass Elliot solo release, but was in fact a Mamas and the Papas record. ("Papa" John Philips famously introduces the song at the beginning).
In any case, here we have Cass singing the song - for laughs - on the Smothers Brothers Comedy Hour. She's doing it live, which is all the more remarkable.