Pop star Madonna is facing a legal battle over the name of her Hard Candy gym chain.

The pop superstar, who has opened branches in Russia and Mexico, has been sued by executives at cosmetics giant Hard Candy, who claim Madonna does not have the right to use the name for her fitness brand, which also includes clothing and DVDs, reports contactmusic.com.

The documents, filed in Florida and obtained by Radaronline.com, accuse the singer of trademark infringement and unfair competition.

Executives at the Hard Candy cosmetics company, which was formed in 1995 and gained a mass following for its popular range of nail polishes, are demanding damages, and want the star to stop using the name.