Organised by The Works, 'Something to Remember' is aiming to raise £2,000 for Charlie's chosen charities the RNLI and the school's Malawi initiative.
The fundraiser takes place on Sunday October 7 in Market Square between 10am and 6pm and features performances from among others the school's jazz band, Mike Carroll Sing-A-Long Classics and DJ Paul Williams.
Other activities include a gladiator arena, bouncy castle, bungee jumping, a boxing showcase courtesy of the DeLick Academy, face-painting, a raffle and more.
There are plenty of food options provided by The Works including a hog roast, waffles, American Pancakes and homemade ice-cream.
The Works are organising the event because of their association with Aylesbury Grammar through their sponsorship of the school's rugby team.
Restaurant manager Matt Bowen said: "Every year, Charlie enjoyed holidays in Devon and often interacted with the life guards on the beach, so it is for this reason the event will be raising funds for the lifeguards at Croyde Beach via the Royal National Lifeboat Institution (RNLI), along with the Malawi initiative, which Charlie got involved with while attending AGS.
“Charlie's fundraising activity went towards putting a new roof on the infant school and providing new mattresses for the dormitories, and he was also lucky enough to go to Malawi and see first-hand how these improvements helped support the children attending the school – an experience that profoundly influenced him.
"We got in touch with Charlie’s family and Aylesbury Grammar School as we really wanted to do something to bring everyone who knew Charlie together; to celebrate his life and help raise funds for the charities that were important to him.
"We sponsor the school rugby team which Charlie was a member of, so we got to know Charlie, and so felt strongly about wanting to do something special in his honour.
"We really hope the local community will join us in remembering and celebrating the life of such a wonderful young man on this very special day.”
Aylesbury Grammar School headteacher Mark Sturgeon said: “Charlie’s character was one of endless energy, fun and selfless contribution. He raised money for our Malawi partnership as well as his involvement in young enterprise as a leader and mentor.
"He is a true Aylesburian, always willing to help others, to be involved in activities and ensure that he gave his best to all he did, always with a smile. We miss Charlie immensely, but his legacy will always ensure we remember the contribution he made and the enjoyment he brought to all our lives.”
To donate towards the charities visit www.justgiving.com/crowdfunding/theworkscharliedunne