Meryl Streep has urged all members of the Congress to add the Equal Rights Amendment to the Constitution on behalf of the ERA coalition.

The Oscar-winning actress took it upon herself to write all 535 members of Congress, personally sign the letters and send them to Washington, imploring them to back the effort.

"I am writing to ask you to stand up for equality - for your mother, your daughter, your sister, your wife or yourself - by actively supporting the Equal Rights Amendment," Streep said in her letter, according to Vanity Fair.

Streep added that the ERA will add "a meaningful benefit for the whole human family," and that it is not just a women's rights issue.

She also sent copies of the book "Equal Means Equal: Why the Time for the ERA is Now," by Jessica Neuwirth, the founder of the ERA Coalition, to the lawmakers, Metro International reported.

Streep has been openly vocal about her political beliefs, and even gave fellow actress Patricia Arquette a standing ovation when she talked about equal rights in her speech at the Oscars this year after she won the award for Best Actress in a Supporting Role for the film "Boyhood."

The Equal Rights Amendment was first written back in 1920, after women had obtained the right to vote.

From 1923 onwards, it was introduced to Congress yearly until 1972, but the amendment floundered in 1982 when it failed to get votes from three states in order for it to be included in the Constitution.

The amendment states: "Equality of rights under the law shall not be denied or abridged by the United States or by any State on account of sex," according to E! Online.