Women in California will get stronger tools to challenge gender-wage disparities under a bill signed Tuesday by California Gov. Jerry Brown. The law is touted as the strongest in the United States by its supporters.

Although the state's existing equal pay law bars employers from paying a woman less than a man for equal work at the same establishment, the new bill broadens its scope. With the Fair Pay Act, workers can also go to court if they are paid less than fellow colleagues with different job titles who do "substantially similar" work, according to a statement released by the governor’s office.

"Sixty-six years after passage of the California Equal Pay Act, many women still earn less money than men doing the same or similar work," Brown said, in the statement. "This bill is another step toward closing the persistent wage gap between men and women."

Authored by Sen. Hannah-Beth Jackson, a Santa Barbara Democrat, the bill protects employees from retaliation for invoking the law and guards those who discuss their pay scales at workplace. It also states that employers can provide higher pay rates for men only if the wage is based on seniority, a merit system, quantity or quality of production or any other "bona fide factor other than sex," the Associated Press reported.

Jackson reportedly introduced the Fair Pay Act after a 2013 study by Equal Rights Advocates, a gender justice group, found that women earned about 84 cents for every dollar men earned. About 1.75 million households in California are run by women and the disparity in the pay scale between the sexes costs families some $39 billion annually, Reuters reported, citing the study.

"Today is a momentous day for California, and it is long overdue. Equal pay isn't just the right thing for women, it's the right thing for our economy and for California," Jackson said in the statement.

The bill received bipartisan support and backing from the state Chamber of Commerce. The new law takes effect Jan. 1.

Several Hollywood actresses also lauded the move.

Actress Geena Davis, who also serves as a chair for California Commission on the Status of Women and Girls, said in the statement: “We can confidently say that fair and equal pay for women in our state is a key priority, and will lead us to a stronger California.”

According to Forbes magazine, Hollywood's best paid actor, Robert Downey Jr., earned $80 million in 2014, compared with Jennifer Lawrence, the highest paid actress, who earned $52 million the same year. 

"The California Fair Pay Act received bipartisan support because women support families and drive our economy. It is a critical step toward ensuring that women in California are seen and valued as equals," Academy Award-winning actress Patricia Arquette said in the statement.