Diane Ford — the mother of Premier Doug Ford and late former Toronto mayor Rob Ford — has died at the age of 85 after a battle with cancer, the premier's office confirms.

In a statement posted on Twitter by press secretary Ivana Yelich, the premier's office said the Ford matriarch died surrounded by her family and friends in Etobicoke Sunday evening.

"Mrs. Ford was an active member of her community who supported numerous charitable causes. But most of all, she was the rock for her family, especially her 10 grandchildren," the statement said.

It adds the Ford family is "extremely grateful for the outpouring of support from members of the community in recent weeks."

"The family would also like to thank Mrs. Ford's caregivers for their compassionate care," it said.

Ford is predeceased by her husband, Doug Ford Sr., who served in the Ontario legislature in the 1990s as well as by Rob Ford, who died in 2016 after a battle with cancer himself.

Rose to prominence during Rob Ford's years as mayor

Diane Ford had long been in the public sphere, with her late husband Doug Sr. serving in the Ontario legislature in the 1990s, but she rose to prominence during her youngest son's turbulent years as Toronto mayor.

She was a fierce defender of Rob Ford as he publicly battled addiction and substance abuse.

"My heart breaks for my son. It really, really does, because he's been attacked," she said in an exclusive 2013 interview with local TV station CP24.

Rob Ford, centre, raised his arms with his wife Renata, right, and mother Diane, left, as he spoke to supporters in Toronto in 2010. (Nathan Denette/The Canadian Press)

She went on to say that while she didn't condone his behaviour, she felt he had been treated unfairly.

"It's not acceptable behaviour. He is the mayor of the city, but he knows that better than anyone now. But, you know, to err is human, but to forgive is divine and we all err, but here there is no forgiveness...Forgiveness isn't in the eyes of the media right now," she said.

She also told interviewers that her son didn't have a drug problem — he had a weight problem.

Just a year later, Diane Ford was yet again in the news. This time, she and several family members donated tens of thousands of dollars to Humber River Hospital, where Rob Ford was then receiving cancer treatment.

"After 42 years of having my children here and using emergency services ... doctors have been wonderful, and it's our hospital," Diane Ford said at the time.

Diane Ford, pictured with late Toronto mayor Rob Ford's daughter Stephanie Ford, wife Renata Ford and son Dougie Ford at a funeral at St. James Cathedral in 2016. (Frank Gunn/The Canadian Press )

Then, in 2018, Doug Ford launched his campaign for premier from his mother's home. The same house had long been the setting of the annual Ford Fest barbecue, to which the whole public is invited.

In recent years, the event has moved to a far bigger venue.

News of Ford's death prompted messages of condolences from all corners of the political spectrum.

Condolences to Premier Ford <a href="https://twitter.com/fordnation?ref_src=twsrc%5Etfw">@fordnation</a> at this time of sadness. I know your mother Diane was close and important to you and will be dearly missed by you and your family. —@Kathleen_Wynne

Throughout the 25 years I have known her, Mrs Diane Ford was so obviously the matriarch of the Ford family and that is why I know they will miss her so much.<br><br>On behalf of all Toronto residents, I am extending condolences to the Ford family tonight as they mourn her passing. —@JohnTory