He has caught the imagination of people across Northern Ireland and the world.
On Thursday 300 people attended a gala ball which paid testament to the groundswell of support for inspirational Belfast tot Oscar Knox.
As the little boy battles for his life Stateside, figures from the world of sports, business and politics joined supporters and relatives for one of the biggest fundraising efforts yet for the child.
The gala event at Belfast’s Europa Hotel was organised in just five weeks.
It followed this week’s devastating news for the Knox family.
American doctors treating young Oscar — who suffers from an aggressive childhood cancer — have discovered he also has a potentially fatal heart condition.
The four-year-old has been diagnosed with pulmonary hypertension, which means that he can no longer receive treatment to stop his cancer returning.
The family had managed to raise a massive £250,000 to take Oscar to America and pay for the cutting-edge treatment there.
But the message at last night’s gala ball was — “we will keep on fighting”.
Oscar’s aunt Martina McMenamin (20) said: “The particular treatment we had started fundraising for is not an option now due to whatever showed up on his tests, but that’s not stopping us battling on.
“Oscar is still battling like he always does. He’s fighting on and we should do the same. It’s up to us to keep boosting the funds.
“To know that we are over here holding this night in support of Oscar, it’s great for them (Oscar’s family) when they are on their own dealing with all of this.”
Among items auctioned at the ball was a hat and shirt signed by golfers Rory McIlroy and Darren Clarke, alongside canvasses of Olympic medal-winning boxers Paddy Barnes and Michael Conlan. Belfast fighter Conlan said: “I would give up my Olympic medal for him (Oscar) to be cured.
“We supported Oscar the whole way through the Olympics.
“For anyone to go through what he’s going through with a smile on his face is unreal. My heart goes out to him.”
Barnes said he fought his quarter- final Olympic bout for Oscar — after he saw a picture of the Belfast tot holding a poster backing him.
“I saw that picture two days before I was fighting the quarter-final for the medal,” he said.
“I was nervous and that gave me a real lift, it fired me up.”
Among the sporting personalities — including the Ulster Rugby team and Tyrone manager Mickey Harte — were more unlikely faces.
They included the Ireland football fans from Limerick who were pictured with the ‘Angela Merkel Thinks We’re At Work’ flag at the start of this summer’s Euro 2012 championship.
Chris Farrell from the Ulster Rugby team said: “You can see from the reactions here everyone is supporting Oscar.”
Tierna Cunningham, Belfast’s Deputy Lord Mayor, added: “I’m a mum myself. Oscar’s mum and dad inspire me so much.”