The 45-year-old has already received rave reviews at the Toronto Film Festival, where the cast were given a standing ovation, apparently reducing Jen to tears.
According to reports, the film will hit cinemas for one week in December in order to qualify for Academy Awards consideration, with a wider release date set for January 2015.
It could be a career-changing role for the star, who is best known for her comedic performances.
"It was a no-brainer," Jen previously said of her decision to sign up to the film. "Just reading Patrick's script I actually saw myself doing it. I just felt like it was already happening and it was pretty easy to say, 'Yes'.
"It was such a beautiful, complex, layered, tortured character. I just tapped into something I was meant to do."
The film's producers have stated that Jennifer was their only choice when casting the movie.
"When my life and producing partner Ben Barnz and I first read Cake just 14 months ago, we knew we had to go to Jennifer Aniston," director and executive producer Daniel Barnz said.
"It was the most obvious un-obvious choice – she's mega-talented, but we've never seen the whole range of her extraordinary comic and dramatic abilities showcased in one role."