Thirteen people died after a van was driven down the world famous Spanish boulevard at high speed.
After days of appealing for information about his fate, Julian's family have now confirmed he was one of the victims.
"Julian was a much loved and adored member of our family," the family said in a statement overnight.
"As he was enjoying the sights of Barcelona with his mother, Julian was sadly taken from us."
Julian's mother Jumarie, known as Jom, was also seriously hurt in the assault. She is still being treated in a Barcelona hospital.
