Four-year-old Frankie Sherwood passed away on Monday morning after a battle with the childhood cancer neuroblastoma, his family announced on their Facebook page.
The young boy, from Dudley in North Tyneside, was diagnosed at just 15 months old in May 2015. He underwent several bouts of treatment but the cancer kept coming back.
His family had hopes of taking him to America for pioneering treatment although in January they were told it was too late.
Frankie was a devoted Newcastle supporter and was well-loved by the club's fans. In November 2016 he led out the team in front of thousands for their match against Blackburn Rovers.
In a tweet Newcastle gave their condolences to Frankie's family.
Other people took to Twitter to express their grief and show support for Frankie's family. One person tweeted: "Rest in peace little fella, taken too soon. Your bravery throughout your fight was an inspiration."
Another tweeted: "Such sad news that young Frankie Sherwood passed away during the night. Showed such bravery and strength. Thoughts are with his family #RIPFrankie"