LOS ANGELES (Reuters) - Music producer Russell Simmons said on Thursday he was stepping down from his fashion and production businesses after a screenwriter said in a column in the Hollywood Reporter that Simmons sexually assaulted her in 1991.

Jenny Lumet, the screenwriter daughter of the late movie director Sidney Lumet, in a Thursday Hollywood Reporter column accused Simmons of forcing himself on her in his New York apartment in 1991.

Simmons, 60, the co-founder of hip-hop label Def Jam Records and also a film producer, apologized for his behavior in a statement on his Instagram site.

Reuters could not independently confirm the allegation and representatives for Simmons did not reply to a request for comment.

“While her memory of that evening is very different from mine, it is now clear to me that her feelings of fear and intimidation are real,” Simmons said in his Instagram statement. “While I have never been violent, I have been thoughtless and insensitive in some of my relationships over many decades and I sincerely apologize.”

Lumet could not immediately be reached for comment.

Simmons is regarded as one of the most influential entrepreneurs in the hip-hop world. He also founded the fashion lines Phat Farm and Tantris, and co-produced films and TV shows including “The Nutty Professor” and “Def Comedy Jam.”

HBO said on Thursday it had removed Simmons’ name and involvement in its upcoming six-part series “All Def Comedy,” due to begin airing on Friday and showcasing emerging and established stand-up comedians.

“HBO will be airing All Def Comedy as planned. However, Russell Simmons will not appear in the new series and we will be removing his name from the show moving forward,” the premium cable network said in a statement.

“The series is a platform for promising and upcoming comedians and we do not want to deprive them of an opportunity to showcase their talents to a national audience. We have no other projects with Russell Simmons,” HBO added.

Simmons is the latest powerful man in entertainment to be accused of sexual misconduct. “Today” show host Matt Lauer on Thursday apologized for “troubling flaws” after being fired by NBC television for inappropriate behavior.