Arsenal academy graduate Marcus McGuane has joined Barcelona's B side for an undisclosed fee on a contract that could extend to five years.
The 18-year-old came through the Gunners' youth ranks after joining the London club at under-six level.
England U19s midfielder McGuane has played twice for the Arsenal first team this season, in Europa League ties against Red Star Belgrade and BATE Borisov.
The Spanish club confirmed McGuane would initially join up with the Barcelona B squad and hold an option to extend his contract, which has a buy-out clause set at 25million euros (£22.5m).
A Barcelona statement read: "McGuane's deal will keep him at Barca for three seasons, plus two option years. The buy-out clause has been set at 25m euros."
Arsenal added in a club statement: "We would like to thank Marcus for his contribution and wish him well at Barcelona."