Stormy Daniels, the porn star who catapulted herself and Michael Avenatti to fame with lawsuits against former President Donald Trump, will have a starring role in court beginning Monday when prosecutors try to prove that the California lawyer cheated her of $300,000 in book proceeds.

Her testimony in Manhattan federal court will be pivotal for prosecutors trying to prove Avenatti engaged in wire fraud and aggravated identity theft to keep from giving his client money he had received from her publisher. Opening statements are set for Monday. Daniels is not expected to testify until Tuesday, at the earliest.