Usher Nanny suing for not paying! And wrongful termination

Usher has secretly been stiffing the nanny … financially … this according to a new lawsuit obtained by TMZ.

Cecilia Duncan is suing the singer, claiming Usher hired her as a part-time nanny back in December 2010 and she worked her ass off caring for his two sons (aged 4 and 5) often exceeding 40 hours per week.

According to the lawsuit, Cecilia felt like she was being overworked without being paid overtime … and expressed her concerns to Usher in 2011 that she was being shafted.

Cecilia says Usher ignored her complaints for more than a year … and finally fired her a$$ last September without paying her overtime money.

She’s now suing for wrongful termination, failure to pay wages, and more — demanding unspecified damages. Sources close to the lawsuit tell us she wants in the six-figure range.

A source connected with Usher tells TMZ … this is a frivolous lawsuit and all the allegations made by the former nanny are completely false.