Millions of pounds in donations is raised every year for a growing number of people affected by cancer, with 200,000 people taking part nationwide in schools, workplaces and homes.
Across Yorkshire, hundreds of events are planned, including a coffee morning hosted by Anne Sheehan, owner of AS Music School in Sheffield.
Mrs Sheehan undertook an enormous fundraising challenge last year, walking 1,000 miles from Sheffield to Spain on the Camino de Santiago.
Having known she wanted to do something special to mark her 60th birthday, she chose to dedicate the walk to her parents and raise money for the nurses which had cared for them.
"A camino has got a spiritual aspect to it, whether you're religious or not," she said.
"My mum, my dad and I owe Macmillan a big one, and it definitely gave me the motivation to carry on. I did feel they might be smiling over my shoulder.
This Friday, she will join thousands across the country in hosting further fundraising events as part of Macmillan Cancer Support’s World’s Biggest Coffee Morning.
She will be opening the doors at AS Music School, in Woodseats, from 11am.
Lynda Thomas, chief executive at Macmillan Cancer Support, said: “Macmillan would like to say a huge thank you to everyone hosting a World’s Biggest Coffee Morning so we can be there for people with cancer.
“Everyone who hosts or supports a World’s Biggest Coffee Morning helps Macmillan to run our support line seven days a week and to support our 7,700 Macmillan professionals who support people with cancer.”