She had been diagnosed with bipolar disorder and struggled with depression for many years, her family told the Hollywood Reporter in a statement that sharply criticised Weinstein, McGowan and members of the media for spreading mistruths about her.
McGowan was one of Messick's first clients when she was an entry-level manager at Addis Wechsler, according to the family.
Tina Fey who worked with Messick on adapting of Rosalind Wiseman's book Queen Bees & Wanna Bees for the screen as Mean Girls (2004), said, "This is very sad news and my heart goes out to her family".
The 50-year-old exec was also Rose McGowan's back in 1997, which is when the 44-year-old actress claims Harvey Weinstein raped her. "Rose told Jill what had happened-that she made the decision to remove her clothes and get in the hot tub with him-a mistake which Rose immediately regretted".
The family says that Messick "opted not to add to the feeding frenzy, allowing her name and her reputation to be sullied despite having done nothing wrong".
Rose claimed she told her manager about the incident, and she did nothing.
Messick had recently became the talk of the town after being dragged into the limelight by her former talent.
England v Wales live on the big screen at Sardis
Last weekend's encounter in Rome saw the Australian's side put seven tries on the board - including three in the last 15 minutes. Liam Williams' score and the boot of Leigh Halfpenny had given Wales a 13-8 half-time lead. 12 Owen Farrell (Saracens 54 caps ).
Renuka Chowdhury to move privilege motion against Kiren Rijiju
In another tweet, he said, "Congress says it's a breach of privilege!" Rijiju, however, clarified that he was only trying to show how the PM had kept his cool.
THE 15:17 TO PARIS (not reviewed)
That day, the stakes couldn't have been higher, but these guys all ended up doing the right thing at the right time. And I was like 'Gee this hurts.' And I don't remember it hurting that bad in the moment.
During the same interview, Affleck expressed his support for McGowan and said that he believes her. Weinstein has since denied his non-consensual advances towards McGowan, as well as other women in Hollywood.
"Today she did not survive". She was McGowan's manager in 1997 during the time the actress claims Weinstein raped her, Fox News said.
Messick's family said in a blistering statement.
After working for McGowan, Messick reportedly joined Harvey and Bob Weinstein's Miramax as a production secretary, despite being informed of the alleged attack. Despite this, Jill recognized that Harvey had done something untoward to Rose, if not illegal. But at a later date, McGowan said she felt as if filing a charge against her perpetrator was "useless" as a result of the way her management team treated her. "In the face of inappropriate behavior, Jill handled the situation appropriately".
While Weinstein has yet to be formally charged with a crime, Los Angeles police have taken dozens of reports from women who have accused Weinstein of sexual misconduct while authorities in NY and London are investigating the former studio mogul, NBC News added.
"She never knew any details until recently, when Rose elected to make them public", the family stated.
As a producer, Messick's credits included "Mean Girls", "Baby Mama", "She's All That" and "Frida". She was a terrific producer, there with me every day on set, and always a tireless, positive presence.