“Baby” is a song by Canadian singer Justin Bieber featuring American rapper Ludacris. It was released as the lead single on Bieber’s debut album My World 2.0. The track was written by Bieber, Ludacris, Christina Milian, Tricky Stewart (who had worked with Bieber on the previous single “One Time”) and R&B artist The-Dream, with production handled by the latter two. It was made available for digital download on January 18, 2010. The song was aired immediately upon release, officially influencing mainstream and rhythmic radio on January 26, 2010. The song received positive reviews from critics, who praised the song’s effective lyrics and chorus and praised Ludacris’ Part and the song’s ability to have an urban flavor.

The song was a commercial success, peaking at number one in France and Scotland and reaching the top ten in the UK, Canada, US, Australia, Norway, Japan, Ireland, Hungary, Belgium (Flanders), Slovakia and New Zealand. “Baby” was the fourth most successful single of 2010 in France. The accompanying music video takes place in a mall/bowling alley. There are several sequences in the video, such as Drake, Lil Twist and Tinashe, in which Bieber is chasing a girl. As of May 2013, the song has sold 3.9 million digital downloads in the US and is certified Diamond in the country.