At 10.30am the huge poster was unveiled by TV star Ben Shephard, Harry Potter actors Oliver and James Phelps as well as other celebrities.
The board stands in Birmingham City Centre near to Selfridges.
The charity ball will be held at Birmingham's ICC in October and is aiming to raise over £50,000 for Help Harry Help Others, the charity launched by Harry's mother.
The ball is expected to be attended by many celebrities including England footballer John Terry, Dragon' s Den's very own Duncan Bannatyne, and television presenter Alison Hammond.
Harry's mother Georgina says she is overwhelmed by the support:
– GEORGINA MOSELEY
The Ball will be a super but emotional night and something Harry would be very proud of.Harry was born and bred in Birmingham and he's inspired so many children and adults globally and continues to do so. I really hope companies within Birmingham support this spectacular evening that will hopefully support us so that one day no other family ends up feeling like we do right now.
More than 50 companies in Birmingham have pledged to help out at the event.
Harry died of an inoperable brain tumour in October 2011, after spending his last two years raising money for charity by selling handmade bracelets.