50 Cent has filed a defamation lawsuit against his ex Daphne Joy over her public accusations that he raped and physically abused her, calling them a “calculated attack” of false allegations designed to destroy his reputation.

In a case filed Monday in Houston court, the rapper (real name Curtis Jackson) says Joy (Daphne Joy Narvaez) made her claims as retaliation after the rapper sought legal action to take sole custody of their son in the wake of a lawsuit against Sean “Diddy” Combs that accused Joy of being a “sex worker.”

50 Cent’s lawyers say the allegations against him were nothing more than an attempt to “destroy his personal and business reputation, harm Jackson’s commercial and business interests, negatively affect his custody case, and prevent him from seeing his son.”

“As apparently intended by Narvaez, Jackson has been subjected to extensive public ridicule, hatred, and contempt,” his attorneys write in the complaint, obtained by Billboard. “Jackson brings this action for defamation…in order to vindicate his rights and protect his reputation from Narvaez’s calculated attack.”

Included as an exhibit to Monday’s lawsuit is a letter the rapper’s attorneys sent to Joy last month, demanding that she remove the posts and issue a retraction. They say she responded by demanding “millions of dollars” and for 50 Cent to drop his custody case in return for removal of the post.

“Narvaez refuses to take down or remove the defamatory post unless he complies with extortive demands, including the payment of large sums of money and forfeiting his meritorious custody action,” Jackson’s lawyers write.

Joy could not immediately be reached for comment.

The dispute dates back to March, when Joy’s name was mentioned in a wide-ranging sexual abuse lawsuit filed against Sean “Diddy” Combs by Rodney “Lil Rod” Jones. In that complaint, Jones claimed that Combs had “bragged” about paying Joy and other women a “monthly stipend” for sex.

Days later, Joy posted a scathing statement about Jackson to Instagram: “Let’s put the real focus on your true evil actions of raping me and physically abusing me,” she wrote at the time. “You are no longer my oppressor and my God will handle you from this point on.”

In his lawsuit on Monday, Jackson says that Joy’s blistering accusations were a response to his decision to “take legal action” to seek custody of their 11-year old son Sire in the wake of the lawsuit against Diddy. “Upon learning of the troubling allegations in the Combs litigation, Jackson came to the reasonable conclusion that it was not in his child’s best interest for Narvaez to have full custody,” the suit states.

Courts have made it difficult for “public figures” like a famous rapper to sue for defamation. They must prove that someone like Joy made her statements with “actual malice” – meaning she knew they were false or acted with reckless disregard for the truth. But in Monday’s complaint, 50 Cent’s lawyers say Joy’s “unequivocally false” statements meet that difficult standard.

“Narvaez knows that Jackson did not rape or physically abuse her, yet she knowingly published the false statements to her almost 2 million followers on Instagram,” 50’s lawyers write. “Narvaez published the defamatory post, and refuses to remove it, out of sheer hatred and ill will toward Jackson.”