The new version, which leaked on January 27, features Pitbull replacing the verses which were originally recorded by Juicy J, reported Ace Showbiz.
The original version of 'Dark Horse' appears in Prism, Perry's latest album which became popular after being released last October. Featuring Juicy J, the track was produced by Dr Luke, Max Martin and Cirkut.
As for Pitbull, the Miami-born musician is currently ruling the chart with his Kesha-assisted 'Timber'. The rapper has also collaborated with Jennifer Lopez and Brazilian singer Claudia Leitte for 'We Are One (Ole Ola)', the official song of the upcoming 2014 FIFA World Cup in Brazil.