The 10-second low quality clip of the untitled track unexpectedly hit the web via a fan's Twitter page, reported Ace Showbiz.
"I can't disguise myself/ I've built these walls so high," the former Disney darling is heard singing over the thumping beat.
The song is apparently her duet with ex-boyfriend Justin Bieber, though there's no sign of the Canadian heartthrob's involvement in the snippet.
If the song really features Bieber, it's not Gomez's first collaboration with her former boyfriend to have leaked. The former lovers once also collaborated on another track that mysteriously surfaced online late last year.