Jennifer Garner's next feature film came at just the right time in her life.

"I feel like Miracles From Heaven kind of chose me," Garner told ET. "It felt like something that had just been put out there for me."

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In the faith-based movie, Miracles From Heaven, Garner stars as Christy, a mom who becomes a ferocious advocate for her 10-year-old daughter Anna (Kylie Rogers) when she is diagnosed with a rare, incurable disease. Their lives are forever changed when an extraordinary medical miracle unfolds, leaving specialists baffled and a community inspired.

The movie was offered to Garner following one of the most difficult times in her life when her 10-year marriage to Ben Affleck unraveled.

"The blessing for me for this film is to be reminded of all that really matters, which is the health of your kids and your loved ones and yourself, so you can be with all these people and to be reminded to look for miracles wherever you can find them," said the mother of three.

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The film, also starring Queen Latifah and Martin Henderson (Everest), is based on the best-selling book by Christy Beam, who believes her daughter went to heaven after a near-death experience and was later miraculously cured of a disorder. The 13-year-old on which the story is based, Annabel, now has no symptoms and is not on any medication.

The 13-year-old on which the story is based, Annabel Beam, now has no symptoms and is not on any medication.

Christie said knowing Garner was a blessing.

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"She's messaged me and I've messaged her back, and she has taken the time to really find out and care and ask some really great questions about what it was like during this time," she said.

Miracles From Heaven opens March 18.