Ms. Blanchett, who was awarded best actress at the 2014 Academy Awards for her role as Jasmine in Woody Allen’s “Blue Jasmine,” has been vocal in her support of victims of sexual misconduct in the movie industry.

Following the allegations against Harvey Weinstein which surfaced in October 2017, Ms. Blanchett made a public statement backing the women who accused the producer of sexual misconduct. Speaking to the film industry trade magazine Variety, Ms. Blanchett said, “It is never easy for a woman to come forward in such situations and I wholeheartedly support those who have.”

Ms. Blanchett worked with the Weinstein Company on “The Aviator,” for which she was named best supporting actress at the 2004 Academy Awards.

On Monday, Ms. Blanchett was one of 300 women listed as backing a new campaign against harassment in the workplace. The initiative, called Time’s Up, was announced in a full-page advertisement in The New York Times that called on companies and government agencies to address workplace sexual misconduct. It also includes a $13 million legal defense fund for less privileged women affected by sexual misconduct; other celebrities involved in the campaign include Meryl Streep, Natalie Portman and Emma Stone.

Ms. Blanchett’s appointment has been welcomed by industry insiders. “Cannes really needs to take emergency measures to show its support for women filmmakers at this crucial moment and putting Cate Blanchett upfront, given her support for Time’s Up, is a good sign,” Kate Muir, a screenwriter who is also a campaigner with the group Women and Hollywood, said by email.