 " Knock You Down " is a song by American singer and songwriter Keri Hilson , recorded for her debut studio album In a Perfect World ... ( 2009 ) . The song features guest vocals from Ne @-@ Yo and Kanye West . All three artists co @-@ wrote the song with its producer Nate " Danja " Hills , as well as Polow da Don and Jim Jonsin . The song was released as the album's third single in the United States on November 10, 2009 . " Knock You Down " is an R&B song that samples " Knock You Down " by B.T. " Kno