While battling Alzheimer's disease, Ioanna Alexopoulos' father George could not at times recognise his daughter - nor could she recognise him.
The West Wollongong woman said the sweet, placid father she had once known became a man that would turn into a "monster" who snapped at the smallest of things once the disease had him in its grip.
Ms Alexopoulos, 30, will remember the good times and the bad when she walks in memory of her father as part of the Illawarra Memory Walk & Jog this Sunday.
The event is the major fund-raiser for Alzheimer's Australia NSW, and organisers hope to get 1000 participants for the Illawarra event to help reach a fund-raising target of $100,000.
Funds will go towards support services for the roughly 5300 Illawarra residents living with dementia, their family and their friends.
Ms Alexopoulos said she wanted to raise as much as she could for the charity, and help raise awareness about the disease.
She said her father was left undiagnosed for a decade and was medicated for depression rather than dementia, which added to his - and his family's - confusion.
"If the doctors treating him had more knowledge about dementia then I believe he would have been diagnosed far quicker, and would have passed away peacefully and not in pain," she said.
"As well as raising funds for support services, it's also important to raise funds for research - to one day find a cure. Who knows - I may end up with Alzheimer's."
Ms Alexopoulos said she first noticed changes in her father in 1995 when she was a 13-year-old schoolgirl.
"He'd just retired from BHP where he'd worked for 33 years, and he just started forgetting little things and he would lose his temper really easily," she said.
"Before that he was the most gentle and soft person - the epitome of a good father. But from then on, there was a gradual decline and it was hard to accept he was turning into a different man.
"It was when I was doing my HSC in 2000 that he got really bad - he would get really snappy and really forgetful."
Ms Alexopoulos said it got to the stage where her father could not remember his wife or his only child - and then one day he went missing for hours only to be discovered lying on the side of the road.
He was finally diagnosed with Alzheimer's disease in 2006 and passed away in 2008, aged 74.
"I now want to walk in honour of my beautiful father," Ms Alexopoulos said.
McLeod's Daughters actress Doris Younane, whose mother has Alzheimer's, will MC the Illawarra Memory Walk & Jog at Stuart Park, North Wollongong.
For more information or to register go to www.memorywalk.com.au.