Songfacts®:

• This features Adam Gontier, who is the vocalist for the Canadian band Three Days Grace. "Eicca" Toppinen from Apocalyptica explained to Isabelle Le Maguet in an interview for the French Rock Hard magazine why they used Gontier's vocals on this track: "Adam Gontier's name was submitted to us by the US pole of our label. They did some propositions that we refused, but we were impressed by this artist's vocal timbre. Coincidentally we were actually searching for a hoarse voice for the song, so we just jumped on the occasion."
• Apocalyptica is a hard rock band from Helsinki, Finland consisting of three classically-trained cellists and a drummer.
• This song was originally released in 2007 but was re-recorded the following year for the American release of Worlds Collide.
• Toppinen is the chief songwriter for Apocalyptica, but he relies on others to assist him with the lyrics. He explained to Rock Hard that he wrote this song, "with an American friend of mine, who did those of 'I'm Not Jesus' and 'S.O.S. Anything but love.'" Toppinen added: "Personally I don't think I' m a lyricist at heart, and furthermore it's difficult for me to express myself in steady English."
• This song replaced AC/DC's "Rock 'N Roll Train on top of the Billboard Mainstream Rock Chart.
• "I Don't Care" was written primarily by the Swedish pop architect Max Martin, who crafted most of the song's melody and lyrics. Eicca Toppinen contributed additional lyrics and broader creative input, helping shape the tone and direction of the track. Adam Gontier was involved in the arrangement, but he is not credited as one of the principal songwriters.