who sang one is the loneliest number original
One  is a song written by Harry Nilsson and made famous by Three Dog Night whose cover in 1969 reached #5 on the Billboard Hot 100.The song is known for its opening line One is the loneliest number that you'll ever do.Nilsson wrote the song after calling someone and getting a busy signal. He stayed on the line listening to the beep, beep, beep, beep... tone, writing the song. The song was sung by Nathan Lane and was featured on the soundtrack Stuart Little 2. 2  In 2013, Tracii Guns' League of Gentlemen covered One on the album First Record. 3  Mastodon recorded a cover of the song for the Army of Two trailer.