"Eternally" is a song by Japanese musician Hikaru Utada, from her 2001 album Distance. It was re-arranged in 2008 as "Eternally (Drama Mix)," for the use in the Maki Horikita starring Fuji TV drama Innocent Love. It was released as a digital single on October 31, 2008, and eventually released onto CD in March 2009, on an EMI compilation album I: Zutto, Zutto, Aishiteru(i(アイ)～ずっと、ずっと、愛してる～?).
Innocent Love director Toshiyuki Nakano originally decided that Utada's voice would suit the themes of the drama well. Hearing "Eternally," he felt the song was a perfect choice for the drama, as the song's melody, lyrics and title fitted, in his opinion, as if the song had been specifically commissioned for the drama.
The song is a R&B ballad, featuring an arrangement of strings, background percussion and guitar. The lyrics describe a person addressing their lover, who is describing how much they treasure a single moment they are sharing with this person. They believe that even if they cannot stay with their lover forever, at least "the feeling (they) have now will last forever " (今の気持ちだけはずっと永遠,ima no kimochi dake wa zutto eien?).
The drama mix of the song features a different take of Utada's vocals during the recording sessions of Distance in 2001, however it was given a new mix in 2008. The new version is very similar in structure to the original, however with more prominent strings during the chorus.