Question: Who sang you are my one and only?
Disambiguated questions and answers: question: Who sang you are my one and only love?
Who sang the lead vocals on you are my one and only true love?
Who sang the background vocals on you are my one and only true love?
answer: Eric Hilliard Nelson
Ricky Nelson
Martha Wash
Seduction
Martha Wash
Natural Questions answer: Fred Astaire with Adele Astaire
Sarah Vaughan
Ella Fitzgerald
Whispering Jack Smith
Lee Wiley (from the Wikipedia article "My One and Only (song)")