The girl group rose to fame after winning Cowell's U.K. reality TV show "The X Factor" in 2011, and subsequently signed a contract with his record label Syco Music, but it appears the professional relationship is no more.
Representatives from Syco have confirmed to The Sun newspaper that the quartet is no longer an act under the banner after Syco bosses formally ended their professional relationship with the group's management company, Modest.
"Syco Music will no longer work with Modest Management and therefore any artists signed to that management company," a statement to the publication reads. "We do, of course, wish all artists affected by this decision every future success. Consequently, 'LM5', the forthcoming Little Mix album A&R'd and released on Syco Music, is to be serviced by RCA at the request of Syco and Simon Cowell."
Sources tell the outlet Little Mix, comprised of Jesy Nelson, Leigh-Anne Pinnock, Jade Thirlwall, and Perrie Edwards, fell out with long-time mentor Cowell over several issues related to group's latest album, "LM5", which is due to be released on 16 November.
According to insiders, the girls were upset they had to fight to get writing credit on their hit new track "Woman Like Me", and although Simon eventually granted their request, the damage was done, as his relationship with bosses at Modest Management crumbled.
Little Mix isn't the only international pop act caught up in the chaos of the split - the future of hit boy band One Direction is also now in question. The group, which has been on hiatus since 2016, is also on Modest Management's roster of artists.
One Direction were put together by Simon and the group signed a deal with Syco in 2011, a year after finishing third on "The X Factor".