"I Thought I Lost You" is a pop song performed by both American singer-songwriter and actress Miley Cyrus and actor John Travolta. The song was co-written by Cyrus with producer Jeffrey Steele. It was released to Radio Disney as promotion for the 2008 animated film Bolt and its soundtrack; in the film, Cyrus portrays the voice of Penny and Travolta the voice of Bolt. "I Thought I Lost You" was made after filmmakers requested Cyrus to write a song for the film. The song is a teen pop number whose lyrics speak of getting lost and getting found.
"I Thought I Lost You" was nominated for Broadcast Film Critics Association Award for Best Song and Golden Globe Award for Best Original Song, but lost both to Bruce Springsteen's "The Wrestler" from The Wrestler (2008). The song's accompanying music video has Cyrus and Travolta performing the song in a recording studio and features clips from Bolt. "I Thought I Lost You" was promoted by several live performances by Cyrus.