"Baby" is a popular song by Canadian singer Justin Bieber, featuring American rapper Ludacris. It was released as the lead single from Bieber's debut studio album, "My World 2.0," in 2010.

"Baby" is an upbeat pop and R&B track with elements of teen pop. The song's lyrics revolve around a young love story, expressing affection and dedication to a romantic partner. It captures the innocence and excitement of young love and resonated with Bieber's teenage fanbase at the time.

The song was written by Justin Bieber, Christopher "Tricky" Stewart, Terius "The-Dream" Nash, Christina Milian, and Ludacris. It features Ludacris's rap verse, adding a contrasting dynamic to the song.

Upon its release, "Baby" achieved tremendous commercial success worldwide. It reached high chart positions in multiple countries and became one of Justin Bieber's breakout hits. The song's catchy melody, memorable hooks, and Bieber's youthful vocals resonated with audiences, propelling him to international stardom.

The music video for "Baby" features Justin Bieber alongside several guest appearances, including Ludacris. The video showcases Bieber's energetic dance moves and youthful charm, adding to the song's appeal. It became one of the most-watched music videos on YouTube at the time, accumulating billions of views.

"Baby" received mixed reviews from music critics, with some praising its catchy nature and Bieber's vocal performance, while others criticized its simple and repetitive lyrics. Nevertheless, the song's commercial success and Bieber's rising popularity solidified his position as a prominent pop artist.

Over time, "Baby" has remained one of Justin Bieber's signature songs and a fan favorite. Its infectious melody, youthful charm, and Ludacris's rap verse continue to resonate with audiences who followed Bieber's early career.

Overall, "Baby" represents Justin Bieber's breakthrough into the music industry. Its catchy sound, youthful lyrics, and Ludacris's featured verse made it a memorable hit in Bieber's discography and played a significant role in his rise to global fame.