"Baby" is a song by Canadian recording artist Justin Bieber. It was released as the lead single from the latter half of Bieber's debut album, My World 2.0. The track was written by Bieber with Christopher "Tricky" Stewart and Terius "The-Dream" Nash, both of whom worked with Bieber on "One Time", and also by R&B singer Christina Milian and labelmate, rapper Ludacris. It was available for digital download on January 18, 2010. The song received airplay directly after release, officially impacting mainstream and rhythmic radio on January 26, 2010. The song is uptempo R&B, blending together dance-pop and hip-hop elements, while using influences of doo-wop music. The song has received positive reviews from critics who complimented the song's effective lyrics and chorus, and commended Ludacris' part and the song's ability to have an urban twist. It has become Bieber's biggest hit to date, peaking at number one in France, and charting in the top ten of the United Kingdom, Canada, the United States, Australia, Norway, Japan, Ireland, Hungary, Belgium (Flanders), Ireland, Slovakia, and New Zealand. The accompanying music video takes place in a mall/bowling-alley setting. The video features several cameos such as Drake and Lil Twist, in which Bieber chases after a girl. In July 2010, the video became the most viewed video in YouTube history. Bieber performed the song several times, including Saturday Night Live, and the ninth season of American Idol. Bieber also performed an acoustic rendition of the remix version with Drake at the 2010 Juno Awards. The official remix in the United Kingdom features British hip-hop artist Chipmunk.