A ceremony, described as a “celebration of Oscar’s life”, has been held in St Bernard’s Church, Glengormley, this morning.
The family issued a special invitation saying: “We welcome friends, family and supporters of Oscar to join us in procession from the NI Children’s Hospice at 10.15am on May 11 and onwards to St Bernard’s Church.”
A strictly private cremation will follow.
Brave Oscar died on Thursday at the Children’s Hospice in Glengormley.
He was first diagnosed with the disease in November 2011.
After intensive treatment, ‘Wee Oscar’ was finally given the all clear in April 2013, but it returned in August 2013.
In October 2012, he received specialist treatment in America after his family reached their £250,000 fundraising target to pay for the immunotherapy treatment.
After his initial diagnosis, his parents set up the Twitter account so they could update friends and family on Oscar’s condition each time he was in hospital.
However, the account quickly attracted thousands of followers.
Among them were families whose children have the same condition.
The Twitter account became a phenomenon in June 2012, after a group of Irish football fans posed for pictures in Dublin airport before heading off to the European football championship with a flag saying “Angela Merkel thinks we’re at work”.
Oscar – who had been allowed to stay up late to watch the matches – and his father Stephen, made their own flag saying “My ma thinks I’ll be in bed early” and then tweeted a picture of it.
The ‘Merkel lads’, as they became known, were so touched by the picture they decided to auction their flag to raise money for the toddler.
When they arrived back in Dublin they drove straight from the airport to Mallusk to meet Oscar.
Oscar, was a fan of Glasgow Celtic and the football club joined in the fundraising campaign.
Last July, when Belfast side, Cliftonville, went to Glasgow for their UEFA Champions League qualifier, Oscar donned his green and white shirt and led Celtic out before the game as team mascot alongside captain, Scott Brown.
In a statement on Friday, Celtic said: “This is absolutely devastating news and our thoughts and prayers are with Oscar’s parents, Stephen and Leona, and his little sister, Izzie, at this desperately sad time.
“We can’t even begin to understand the pain of their loss, but I hope that there will be a small measure of consolation in knowing that there was genuine love and affection for Oscar from the Celtic family throughout the world.
“Oscar’s courage throughout his illness was truly inspirational, and it was a real pleasure for everyone at the club to meet Oscar when he was our team mascot last July.”
Belfast boxer Carl Frampton said it was very sad news.
“I’m kind of in shock, because with the wee man, I knew he was very, very sick, but you always expected him to get better because he is such a fighter,” he said.
“It’s just heart-breaking.”