Answer the following Q with stream of consciousness. Passage: "Moon River" is a song composed by Henry Mancini with lyrics by Johnny Mercer. It was originally performed by Audrey Hepburn in the 1961 movie Breakfast at Tiffany's, winning an Academy Award for Best Original Song. The song also won the 1962 Grammy Awards for Record of the Year and Song of the Year.

Question: Based on this passage, who sang the song moon river in breakfast at tiffany's?
The important part for answering this question is: It was originally performed by Audrey Hepburn in the 1961 movie Breakfast at Tiffany's, winning an Academy Award for Best Original Song. Therefore, the final answer is Audrey Hepburn.