REVIEW: Katy Perry 'Prism' New Song 'Walking On Air' Twitter Debut Before Oct. 22 Release Date, Disco-Influenced Track Blends Together Old, New Dance Music [LISTEN]

In the wee hours of the morning on Sept. 30, "Roar" singer Katy Perry debuted another side of her new album "Prism" on Twitter. With an iTunes pre-order of her third studio effort, fans can now listen to album track "Walking on Air."

Katy Cats with good memories will remember "Walking on Air" as the other option to hear post-VMAs when Perry had a tie-in with Pepsi ("Dark Horse" won). But, now fans don't have to wait to hear the song anymore.

"Walking on Air" is a classic disco track, adding yet another different element to the musical mix of "Prism." Opening with a highly '70s-inspired vocal guest singing "Tonight I'm walking on air," the track then explodes into a modern EDM-influenced track, while still maintaining a retro vibe.

As she is apt to do on each of the "Prism" tracks heard thus far, Perry's vocals are strong and powerful on "Walking on Air. "Just when I think I can't take anymore, / We go deeper and harder than ever before / We go higher and higher / I feel like I'm already there / We're walking on air," she blasts into the chorus.

The song is notably lighter, and more airy than the mid-tempo empowerment anthem "Roar" or the crawling, vengeful "Dark Horse." It's more classic Perry, blending together happy-go-lucky love lyrics with a beat that lends itself heavily to dancing and the club. Think: "Teenage Dream: The Complete Confection" track "Come Alive."

Listen to "Walking on Air" below.

"Walking on Air" is not the first non-single track to be released before "Prism" hits stores. Following a Pepsi promotion at the 2013 MTV VMAs, Perry debuted "Dark Horse," featuring Juicy J. Despite not having official backing, "Dark Horse" has done well, debuting at No. 17 on the Billboard Hot 100 and getting regular radio play.

As for official singles, "Prism" is led by the smash hit "Roar." Perry is expected to debut the album's second single, love song "Unconditionally," soon.

Katy Perry's third studio album, "Prism" will be released on Oct. 22.