The Iain Rennie Hospice at Home is hoping that more than 1,000 people will turn out for the annual Goodnight Walk, which last year raised more than £100,000 for the charity.
Helen Mariner from the hospice said that as the event is all about having a good time, it makes sense to ask walkers to wear fancy dress costumes.
She told the Bucks Free Press: "We receive amazing support from the local communities in which we work and I'm sure that people will rise to the challenge to help us get into the record books."
The walk is eight miles long and starts at midnight on June 19th at the Amersham Polish Club in Raans Road.
Walkers who want to get into the spirit of things while pretending to keep the streets safe may decide to select a Batman fancy dress costume for the charity event.