"Knock You Down" is a song by American singer and songwriter Keri Hilson, recorded for her debut album, In a Perfect World....

All three artists co-wrote the song with its producer Nate "Danja" Hills, as well as Kevin Cossom and Marcella Araica.

Part of the song refers to Michael Jackson; coincidentally it was released at the time surrounding the death of the singer.

The song received generally mixed to positive reviews, with critics divided as to whether Ne-Yo and West overwhelmed Hilson's appearance.

Hilson performed the song a number of times, including television appearances such as on The Rachael Ray Show.

In a September 2008 interview with Rap-Up about a recent crop of songwriters becoming singers, Ne-Yo said "For one, I think Keri Hilson’s too freakin’ pretty to be in the background.

"[1] In "Knock You Down", Kanye West makes multiple references to Michael Jackson, and coincidentally, the song was released in numerous territories around the death of the singer.

"[5] Dan Nishimoto of Prefix Magazine said the song had a "4/4 Motown feel on the verses and stuttering drums on the chorus.

[5] Chris Williams of Billboard said "with a vocal assist from Ne-Yo and a clever guest rap by Kanye West, it appears Hilson is intent on a knockout punch of her own.

"[7] Sophie Bruce of BBC Music positively received the song, calling it the album's "biggest potential hit.

"[8] Although Nick Levine of Digital Spy gave the song three out of five stars, complimenting production by Danja, and saying that the song sounded like a more obvious hit than "Return the Favor", he complained that "getting two R&B A-listers to appear on your track should be a real coup, but not when one's got a more distinctive voice than you and the other steals the show with some typically ballsy rapping.

"[2] Quentin B. Huff of PopMatters criticized the repetitive hook, stating "Hook-wise, it’s a little like listening to an album of kids chanting while playing double-dutch.

[25] The video begins with Hilson slowly falling backwards onto a bed, and then West appears and raps the introduction.

Hilson and West begin to caress each other, as she is shown in several seductive poses in a bed and sings in front of a white backdrop.

Melinda Newman of HitFix positively received the video, stating "its success lies solely in the charisma and believability that the trio brings to the small screen, which is considerable.

"[26] Margeaux Watson of Entertainment Weekly said, "Though their scenes together are G-rated in comparison to Ciara's steamy romp with Justin Timberlake in their new clip for 'Love Sex Magic,' Hilson’s solo shots in bed are undeniably hot.

"[27] In an interview on the Today Show, anchor Hoda Kotb made a remark to Ne-Yo, stating, "You have this really hot new video that you do with Kanye West and another woman named Keri.

[34] Hilson performed the song and "Energy" with British singer-songwriter Taio Cruz at the MOBO Awards 2009, which she co-hosted, on October 4, 2009.

[35] On January 1, 2010, she performed the song as a part of her set list of Dick Clark's New Year's Rockin' Eve with Ryan Seacrest.