We know what you’d probably answer, and you’d be incorrect.
Amazingly, Williams never took his signature song, Moon River, to the top of the charts. Though he sang the song for the 1962 movie Breakfast at Tiffany’s and catapulted the song to iconic status, it never was released as a single, so Williams’ trademark tune never got a chance to chart.
But the man lent his distinctive silky-smooth voice to 43 albums and 79 singles, and his popular variety show was a cornerstone of 1960s television.
Williams is an indispensable part of America’s soundtrack, and we are thankful that his voice always will be with us.
Oh, and to answer the original question: The song was Butterfly, in 1957.