Hours after Weinstein's New York trial started on Monday, Los Angeles District Attorney Jackie Lacey charged Weinstein with the sexual assault of two unidentified women in 2013.
Weinstein, 67, has pleaded not guilty to charges of assaulting two women in New York. He faces life in prison if convicted on the most serious charge, predatory sexual assault.
The once-powerful film producer is known for reshaping movie-making with low-budget, critically acclaimed films such as "The English Patient" and "Shakespeare in Love."
The Los Angeles charges come as potential jurors in New York were scheduled to arrive at court on Tuesday and fill out questionnaires to determine if they are able to be impartial.
A second phase of selection, in which a final jury of 12 will be picked, is expected to begin a week later, though Judge James Burke has called that date “optimistic.”
Given the high-profile nature of the case, the court cast a wide net, sending out jury summonses to 2,000 New Yorkers. Based on past experience, a court spokesman said about 500 were likely to show up for jury duty.
Lucian Chalfen, a spokesman for the Office of Court Administration, said the number of jurors summoned for Weinstein is roughly five times the number for a typical trial.
Jill Huntley Taylor, a jury expert at the trial consulting firm Dispute Dynamics, said the new charges announced Monday in Los Angeles would increase the challenge of picking a fair jury.
"It's one more opportunity for jurors to be exposed to the allegations against him," she said.
Prosecutors need 12 jurors to back a conviction, while Weinstein needs just one holdout for a hung jury.
Donna Rotunno, one of Weinstein's lawyers, has said she is confident her team could seat a fair-minded jury.
"Once 12 people are put in that box and they realize the gravity of it, they really want to be fair,” Rotunno told Reuters.
More than 80 women have accused Weinstein of sexual misconduct dating back decades.
Weinstein has denied the allegations, saying any sexual encounters he had were consensual.
The allegations propelled the #MeToo movement, which led to men in politics and business being expelled from positions of power following accusations of sexual misconduct.
Allegations against Weinstein first were reported in the New York Times and The New Yorker magazine in October 2017.
The New York prosecutors have charged Weinstein with assaulting former production assistant Mimi Haleyi in 2006. Prosecutors say Weinstein raped the second woman, who has not been publicly identified, in 2013.
Experts said lawyers for Weinstein and the prosecution would need to be wary of jurors who may try to mask their bias in order to serve on a headline-grabbing trial. Some jurors may seek to use the trial as a means of advancing a personal cause, a concern in a case that has become a flashpoint for ending sexual harassment.
“They may think, ‘I want to be the one to make sure he goes to jail. I want to be the one to do justice,’” said Roy Futterman, a New York jury consultant.
Weinstein in October lost a bid to move the trial to suburban Long Island or to Albany, New York state’s capital. He said intense media scrutiny made it impossible for jurors to give him a fair trial in Manhattan.
The defense asked at Monday's hearing that the jury be sequestered, a request the judge denied.