Dublin's 3FE has announced that it will be giving its coffee away for free on Friday.

The south Dublin cafe will adopt a Radiohead-style 'pay what you want' model - with all contributions going to help Rashel Winn, a friend of owner Colin Harmon who has been diagnosed with cancer.

"This morning I woke up in Melbourne to an email from Ger O'Donohue from First Draft, explaining that his business partner, our friend and Ireland's Brewers Cup Champion Rashel Winn has recently taken a setback in her fight against cancer," Mr Harmon wrote in a blogpost.

He explains that the family is now raising money to be with their daughter during this difficult time - and the shop is trying to do what it can to help:

"We made a cash donation but wanted to do something more and so this Friday at 3fe we are not going to charge for coffee in the shop. Instead, there's going to be a big bucket on the counter and you can pay what you like as a donation to Rashel's cause. If you want to pay a little more than you usually would, that's also completely fine."

The day after St Patrick's day is sure to be a busy one for 3fe - the family also has a FundIt page for online donations.