Five-year-old Seth Lane from Corby captured the hearts of millions across the world when he asked people to wear yellow on the day of his vital bone marrow transplant.
A social media video went viral, with celebrities such as Ashton Kutcher tweeting their support for Seth and wishing him well ahead of the life-changing procedure in May.
Now the brave little boy behind the #WearYellowforSeth phenomenon is back at home and on the road to recovery after spending six months in a so-called bubble - a sterile and germ-free unit at Newcastle Infirmary.
If his mum and dad had a cold, they were not allowed in, which made so many simple things, like giving him a cuddle or playing a game with him, very difficult.
So, Seth made a plea to show him support. Not only did it go viral with 30 million hits on Facebook, the response was phenomenal worldwide.
Seth's parents, Nik and Leanne, hope he will be able to return to school in January and say they are "overwhelmed" by the support.
The Bubble Foundation that supports the life-saving work of the Bubble Unit is launching its biggest ever fundraising appeal.