Although Gyllenhaal, 37, does not follow the religion, a lot of her celebrity friends do, which has caused a rift between the two women.
Remini, 47, infamously ditched Scientology before publicly claiming that it nearly destroyed her life.
After leaving the church, Remini was an out-spoken critic and then went on to produce the hit A&E show Scientology and the Aftermath, which was nominated for the Best Informational Series Emmy.
An insider revealed: “Maggie and Leah used to be close but they’ve had an epic fall-out.
“The problem, is that Maggie grew up with a lot of people who were raised in the Church and is still friends with some of them like Michael Pena and Giovanni Ribisi.”
“So this is really car-wreck television for her.”
Leading Scientology figures slammed Remini and the production, claiming that it was totally fake.
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