Registration is now open for the short jog, five and 10 kilometre runs.
Ex-light heavyweight boxing champion John Conteh will launch the runs at 9.30am on Sunday, September 7.
More than 1,000 people take part each year – some keen to beat their previous year’s time, others to simply have fun and raise money for a fantastic cause.
The runs take place in the grounds of Harefield Hospital in Hill End Road, Harefield.
All money raised will go to the hospital’s heart and lung appeal.
The events alongside the run will include a dog show, an all-day barbecue, a fancy dress competition, arts and crafts stalls, a children’s race, and a medieval re-enactment.
To take part, visit www.rbhcharity.org/harefield-fun-run.
Entry costs £10 for adults and £5 for children.