Jennifer Aniston is grieving the loss of her mother Nancy Dow.

Dow passed away aged 79 after suffering from an unknown ailment, and the former Friends star confirmed the unfortunate news on Wednesday (25May16) night.

A statement from Jennifer to People magazine reads: "It is with great sadness that my brother John and I announce the passing of our Mother Nancy Dow. She was 79 years old and passed peacefully surrounded by family and friends after enduring a long illness. We ask that our family’s privacy be respected as we grieve our loss."

Various reports suggest former model Nancy had been suffering from a series of strokes and had lost the ability to speak and walk.

According to In Touch magazine, Jennifer visited her ailing mother for the first time in nearly five years earlier this month (May16) after learning of her estranged mum's illness.

Jennifer initially stopped speaking to her after the publication of Nancy's book From Mother And Daughter To Friends: A Memoir in 1999. The actress was angry about revelations Dow made in the book, which charted their relationship.

But in an interview with The Hollywood Reporter last year (15), Jennifer insisted they are now on good terms, despite their tumultuous past.

"We're all fine," she admitted. "She had a temper. I can't tolerate that. If I get upset, I will discuss things. I will never scream and get hysterical like that. But I was never taught that I could scream. One time, I raised my voice to my mother, and I screamed at her, and she looked at me and burst out laughing. She was laughing at me for screaming back. And it was like a punch in my stomach.

"She was critical. She was very critical of me. Because she was a model, she was gorgeous, stunning. I wasn't. I never was. I honestly still don't think of myself in that sort of light, which is fine. She was also very unforgiving. She would hold grudges that I just found so petty."

And Jennifer added it is just not in her nature to hold grudges against others, saying she is forgiving "probably to a fault."

She continued, "There are people in my life that are like, 'How do you even talk to that guy?' But what's the point of holding on to (anger)? That's so toxic. We're human beings. Human beings make mistakes. Human beings are not perfect. And by not forgiving someone, it's not allowing human beings to evolve and become better people."

Jennifer is the only daughter of Nancy and actor John Aniston, whom she was married to from 1965 to 1980.

Nancy was previously married to musician Jack Melick, and they have a son called John T. Melick III, a director in Los Angeles.

Like her daughter, Nancy was also an actress, appearing in series such as The Beverly Hillbillies, The Wild Wild West, and 2004 drama Pure.