"Baby" is a song by Canadian singer Justin Bieber featuring American rapper Ludacris. It was released as the lead single on Bieber's debut studio album, My World 2.0. The track was written by the artists alongside Christina Milian and producers Tricky Stewart and The-Dream. 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 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 is widely regarded as one of the defining songs of modern-day popular music and continues to find audiences globally.