Katy Perry is spilling the details on the inspiration behind her latest single, “Wide Awake.” The track marks the end of her Teenage Dream era, and will appear in her upcoming movie Katy Perry: Part of Me.

The singer recently told MTV News, “it’s kind of the perfect last word of me at this moment.”

Perry originally penned “Wide Awake” as the end-title song for the film, which hits theaters on July 5.

“It was a song that I hadn’t written for Teenage Dream,” Perry said in the interview. “I was doing this movie and they asked me if I wanted to write an end-title song for the movie and I was like, ‘I know exactly what I want to say.’ I was really kind of dying to write another song at that point.”

Perry added that she did not want to wait for her next album to release new music so “Wide Awake” was included on the re-release of her last album.

A music video for the song premieres tomorrow night on MTV at 7:53 p.m. ET, and, according to Perry, reflects the ups and downs of her life and career over the past year.

“I just wanted to tell a story about myself going through this journey, maybe sometimes trying to get out of the maze. I think what probably kept me going is just the purity of my belief in music.”

Most recently, Perry tore up the stage at Canada’s MuchMusic Video Awards on Sunday night, giving fans a taste of what to expect in her movie, which features live performances, as well as behind-the-scenes footage. She also took home the UR Fave: International Artist award and the International Video of the Year award for “Last Friday Night.”

- Nee-Sa Lossing CBS Local