As Popdust previously reported, the 44-year-old caused a furor when she left the Church in 2013, claiming she did so for the sake of her daughter.
The King of Queens actress tweeted, "Thank you to the brave who did something about it. And to those who didn't have a voice, you do now."
Alex Gibney's controversial film examines the methods employed by the Church of Scientology, and features former Scientologists' accounts of the chilling abuse, blackmail and threats they allegedly endured while they were members.
The documentary also alleges that Scientology star member Tom Cruise's then wife, Nicole Kidman not only had her phone tapped in case she spoke to non-members about her marriage, but that her children, Isabella and Connor were turned against her so that Cruise would have a better case for custody after the couple split.
Not surprisingly, The Church has slammed the documentary, calling it a "bigoted propaganda piece" with "at least one major error every two minutes."
Both Scientology head David Miscavige and Tom Cruise declined to be interviewed for the documentary.