"Lost" is a song by Canadian crooner Michael Bublé, released as third single from his third major label studio album, Call Me Irresponsible. The song was inspired by the breakup with his former fiancée Debbie Timuss. The song was released as a single on November 12, 2007.
In promotion of the single, Bublé performed the song on The X Factor on December 8, 2007. The song was also featured in the sixth season of American police procedural drama NCIS. It featured in a scene in the episode "Heartland", in which Agent Gibbs leaves the town of Stillwater while recalling how he met his first wife. The song was later covered by Jann Arden, a co-writer of the song, for her album Free. The song was a moderate success worldwide. In Canada, the song peaked at #25, while in the United States, "Lost" peaked at #97, making it Michael's third highest entrance in the chart. It also had fair success in the United Kingdom, where it peaked at #19. In Norway, the song peaked at #14. "Lost" was later nominated for a Juno award in 2009.