Credit: Gareth Cattermole/Getty Images

Jennifer Aniston's mother, Nancy Dow, recently suffered a serious stroke, Us Weekly has confirmed.

The actress, 42, visited her ailing mother at an L.A.-area hospital on Friday.

At her side for the ordeal was beau Justin Theroux.

"Justin has been very supportive and there with her all the way," a source tells Us.

"It's a very hard time for her right now."

Aniston's rep wouldn't confirm the news -- telling MSNBC "this is a private family matter."

Aniston and Dow, 75, were estranged for a decade after Dow spoke about their complicate relationship in a 1996 interview and wrote about it in a book, From Mother and Daughter to Friends: A Memoir. They have since reconciled.