Currently, women in Georgia are allowed to undergo the procedure until their 20th week of pregnancy.
Dozens of other celebrities, including Amy Schumer, Sean Penn, Alec Baldwin, Don Cheadle, Rosie O'Donnell, Patton Oswalt, Sarah Silverman and Mia Farrow signed the letter in support.
"This dangerous and profoundly flawed bill mimics many others that have already been deemed unconstitutional," said the letter, whose copy was tweeted in Milan on Thursday. "As men who identify themselves as small governmental conservatives, we remind them that the government is never greater than when it is in the body of a woman or in her doctor's office."
There are several film and television productions in Georgia A letter threatens a boycott if the law is converted into a state law.
"We want to stay in Georgia and continue to support the wonderful people, businesses and communities we love in the Peach state," the letter said. "But we will not silently do that, and we will do everything in our power to bring our industry to a safer state for women when HB 481
The Writers Guild of America released a statement on Tuesday saying Passage Legislation could cause Georgia to lose Hollywood productions.
"This bill would make Georgia an inhospitable workplace for the film and television industry, including our members," the Writers' Union said in its statement. "If the Georgian Legislature and Governor Kemp pass the HB 481 Act, it is quite possible that many of our industries either want to leave the state or decide not to bring any productions there – the potential cost of an obvious attack on each of them Right of the woman to control her own body. "