A community Armed Forces Day will be held during the event, boasting a raft of on-site entertainment – including a 35-metre assault course and even a wartime swing band.
A Second World War-themed marquee will feature a military museum for the older generations to enjoy, while there will also be a bouncy castle and food stalls on hand to keep the children happy.
Visitors can even indulge in vintage afternoon tea while a Big Band blasts out nostalgic hits from the war years – with pre-booking recommended.
Earlier this month festival organisers launched a “Do it for...” campaign urging those signing up for the challenge to snap a selfie of themselves holding a piece of paper or card with their chosen cause written across it, before sending it in to the event’s Facebook page.
Terry Crossley, who has organised the festival since it launched in 1998, said: “As an ex-forces man, I am proud and privileged to be part of an event that engages with the community and reminds the public of the support the armed forces provide in disaster relief and peacekeeping – putting their own lives on the line and much more.
“This will offer the opportunity to thank veterans and serving personnel and encourage the reservists and cadets.”
The Great Scottish Walk and Run Festival is returning to Edinburgh after an absence of six years, boasting a brand new route and a variety of different stalls and activities to keep all members of the family entertained.
As well as military vehicles and stands, there will be face painting, giveaways and demonstrations from birds of prey.
The friendly event – backed by the Evening News – will kick off at 11am on Sunday at Holyrood Park, with walkers given the choice of taking part in either the 10k or 20k routes.
The Great Scottish Summer Run, meanwhile, offers 5k and 10k challenges around Holyrood Park, while the more leisurely Golden Mile Walk offers one-, two- or three-mile routes designed for those who want to take things a bit easier.
Elsewhere, the Great Scottish Toddle gives children under six the chance to join the adults and raise money for charity – with goody bags and entertainment promising a fun day out for all.
On-site music will be provided by community choir The Edinburgh City Singers, with radio station Castle FM broadcasting live throughout the day if those taking part have any special requests in memory of a loved one or just want to embarrass their dad on Father’s Day.
All the money raised by walkers, runners and toddlers goes directly to their chosen charity.