It has been two decades since 200 men, women and children gathered to have their heads shaved for the first World's Greatest Shave event.
This year, on the event's 20th anniversary, thousands of people are expected to shave, cut or colour their hair to raise awareness and money for the 35 Australians who are diagnosed with blood cancer every day.
Northern NSW resident Cathy Mooney said she started the World's Greatest Shave in 1998 to raise money for her father who was going through bone cancer treatment in Lismore.
Sadly he died a year later.
The day after Mooney and her two brothers shaved off their hair in 1998 they climbed onto the helipad outside their father's hospital room to tell him how much money they had raised.
"We rang dad, with our bald heads, to tell him to 'look out your window'," Ms Mooney told AAP.
"And we were holding signs saying 'We raised $80,000'. He got quite teary".
Ms Mooney said the support from millions of people willing to lose, cut or colour their hair for people going through cancer treatment over the past 20 years had been "overwhelming, amazing and humbling".
Mooney and her dad's haematologist partnered with the Leukaemia Foundation to turn a small town event into a nationwide campaign, to help survivors of blood cancer that claims about two Australian lives every two hours.
The public is invited to shave, colour, or have their hair cut by a team of hairdressers at Sydney's Martin Place on Wednesday.
The event runs nationally until Sunday March 18.
