Ronan Farrow Slams Hollywood Support for Woody Allen After Sexual Assault Claims, Ahead of Cannes

— -- Ronan Farrow is once again raising his sister Dylan Farrow's accusations of sexual assault against their father Woody Allen, ahead of the director's film opening at Cannes today.

In a guest column for The Hollywood Reporter, Ronan explained why he is still speaking out on behalf of his older sister, who alleged in a 2014 open letter to The New York Times that their adoptive father, Allen, sexually assaulted her at age 7. He questions why, despite his sister's claims, Allen remains beloved by stars and is earning millions to create a new series and film for Amazon, and is rarely "interrogated" by the media.

"That kind of silence isn't just wrong. It's dangerous," Ronan said. "It sends a message to victims that it's not worth the anguish of coming forward. It sends a message about who we are as a society, what we'll overlook, who we'll ignore, who matters and who doesn't."

As Allen walks the red carpet at Cannes to promote his new film, Ronan said he will essentially get a free pass.

"He'll have his stars at his side -- Kristen Stewart, Blake Lively, Steve Carell, Jesse Eisenberg," he wrote about the director's Cannes appearance. "They can trust that the press won't ask them the tough questions. It's not the time, it's not the place, it's just not done.

Ronan added that it also hurts his sister to see some of her favorite stars lining up beside the director.

"'It's not personal,' one once told me. But it hurts my sister every time one of her heroes like Louis C.K., or a star her age, like Miley Cyrus, works with Woody Allen," he wrote. "Personal is exactly what it is -- for my sister, and for women everywhere with allegations of sexual assault that have never been vindicated by a conviction."

Dylan, along with her brothers Moses and Ronan, were at the center of a 1993 custody battle between the director and their mother, actress Mia Farrow. The couple ended their 12-year-relationship after Allen began a relationship with Mia Farrow's then 19-year-old daughter Soon-Yi Previn, whom she had adopted with ex-husband, composer Andre Previn.

At the time of the breakup, Mia Farrow accused Allen of molesting Dylan. Allen has consistently denied the abuse allegation, maintaining his ex coached their daughter into making the claims, and Connecticut authorities ended their investigation into Allen without filing any charges against the director. Allen then married Soon-Yi in 1997.

When the allegations resurfaced with Dylan's letter in The New York Times, Allen's lawyer dismissed them as a story "engineered by a vengeful lover."

"It is tragic that after 20 years a story engineered by a vengeful lover resurfaces even though it was fully vetted and rejected by independent authorities. The one to blame for Dylan's distress is neither Dylan nor Woody Allen," Allen's attorney Elkan Abramowitz said in a statement to CNN at the time.

Abramowitz did not immediately respond to ABC News' request for comment about Ronan's current column.

For his part, Ronan admitted that although he believed his sister, he at first discouraged her from speaking out in 2014.

"My sister's decision to step forward came shortly after I began work on a book and a television series," he wrote. "It was the last association I wanted. Initially, I begged my sister not to go public again and to avoid speaking to reporters about it. I'm ashamed of that, too."