Gyllenhaal is one of a number of female leads to call out the Hollywood powers that be for sexism and ageism in recent months, as the studios fall under increased scrutiny for gender discrimination.

With dismal numbers of women in lead or directing roles (a 2013 study found women take just 28% of speaking parts in film), the American Civil Liberties Union recently put in a formal request for federal agencies to investigate Hollywood over "overt sex stereotyping and implicit bias".

Just last month, comedian Amy Schumer produced a brilliant - and scathing - critique of ageism in Hollywood, in a hilarious video co-starring Julia Louis-Dreyfus, Tina Fey and Patricia Arquette.

In February, Arquette used her Oscars acceptance speech for Boyhood to launch a rallying call for wage equality in Hollywood and beyond, as those in the audience - including Meryl Streep and Jennifer Lopez - whooped and cheered her on.

And Twilight star Kristen Stewart is the latest name to join the cause, branding Hollywood "disgustingly sexist".

"Women inevitably have to work a little bit harder to be heard," she told Harper's Bazaar. "It's crazy. It's so offensive it's crazy."

At 37, Maggie Gyllenhaal told she is 'too old' to play the love interest of a 55-year-old man