The record was stocked in a music store in Mexico nearly an entire week before its official release date and fans who got the copies spread them online, reported Ace Showbiz.
A fan shared on Twitter photos of "Glory" which showed collaborators on the set including Justin Tranter, Julia Michaels, Young Fyre, Sterling Fox, Oak, Phoebe Ryan, Burns, Nick Monson, Mattman & Robin, Cashmere Cat, Robopop and more.
"Glory" contains previously released songs "Private Show", "Do You Wanna Come Over?" and "Clumsy", and has the party theme.
"What You Need" is described as a blast of horns and southern flavor, "If I'm Dancing" channels Major Lazer's music while "Just Luv Me" channels Justin Bieber's latest hits.
"Coupure Electrique" reportedly features Spears, 34, singing in French throughout.
Spears' ninth studio album is expected to make its debut at No. 1 on the Billboard 200 chart next week.