The teenage playmaker has put pen to paper on a five-year contract with the Spanish giants after his transfer from Dinamo ZagrebBarcelona's new signing Alen Halilovic spoke of his delight at joining the "biggest club in the world" as he put his signature to a five-year contract.
The 17-year-old joins the Catalan giants from Dinamo Zagreb for a €2.2 million (£1.8m) fee which could rise significantly depending on appearances.
And the Croatia international, who will join Barca's B team before making the step up to the senior squad, said he is looking forward to start playing for his new club.
"This is a great day and I am very happy," he said at his unveiling on Monday.
"I have always been a Barca fan and I know a lot about the club. I have been watching Barca B this season – they are a young team who play great football.
"I can speak a little Catalan. I’m very happy to have been given the chance to play at the biggest club in the world. Hello to all the Barca fans and Visca el Barca!"