The actor will appear in the show's upcoming season premiere, TV Guide reports.
He will play an Italian dignitary who is accused of rape.
The storyline is thought to be based on the Dominique Strauss-Kahn case, in which the head of the International Monetary Fund was accused of sexually assaulting a maid. Strauss-Kahn has denied the charges.
A source confirmed that the episode of Law & Order: SVU is inspired by the case but a spokesperson for the show's production company clarified that the drama is fictional.
Nero has previously appeared in movies including Die Hard 2 and Letters To Juliet. He also provided the voice for Uncle Topolino in Cars 2.
Kyle MacLachlan, Paige Turco and TR Knight have already signed up to guest star in the new season of Law & Order: SVU, which will premiere on September 21 on NBC.
Watch a promo for Law & Order: SVU's 12th season finale below: