Blog: Prefixmag.com

Keri Hilson keeps some impressive company. Her debut album, In a Perfect World..., features contributions from Lil Wayne, Timbaland, Justin Timberlake and Ne-Yo, and she was joined by Kanye West for this performance of "Knock You Down" on Letterman last night (May 4). There's some amusing interplay between West, Hilson, and her dancers as he briefly takes the stage, causing Letterman to say he feels "so old" as he greets them all at the end of the song. In a Perfect World... is out now on Interscope Records.