Usher Sued by Ex-Nanny Over Alleged 

Payment Stiffing 

A former nanny of Usher's has filed a lawsuit against the handsome singer.

Cecilia Duncan says she was hired as a part-time employee in December 2010 and logged over 40 hours per week caring for Usher's young sons.

She supposedly expressed concern to The Voice judge over this heavy work schedule, but received no sympathy from Usher - and, even worse, no payment for overtime when she was fired in September 2011.

Duncan is therefore suing for wrongful termination and failure to pay wages and is asking the court for unspecified damages of at least $100,000.

An insider close to the artist tells TMZ that the lawsuit is frivolous and the allegations hold no merit.