|Fabregas became Arsenal's youngest first-team player in 2003 [GALLO/GETTY]
Arsenal midfielder Cesc Fabregas has passed his medical and signed a five-year contract with Barcelona, the European champions said in a statement.
Monday's move completes one of the most protracted transfer sagas of modern times, his boyhood club finally getting their man after chasing him for three years.
According to media reports, Arsenal have received around $56.86mn for their captain.
Barcelona said on Monday there was a buyout clause of $286mn in his new contract.
The 24-year old could make his debut in the second leg of Barcelona's Spanish Supercup tie with Real Madrid at the Camp Nou on Wednesday. Barca and Real drew 2-2 in the first leg on Sunday.
Fabregas came through Barcelona's youth academy at the same time as Lionel Messi, the current world player of the year, before joining the north London club in September 2003.
He became Arsenal's youngest first-team player in the following month when he made his debut aged 16 years and 177 days.
He also became Arsenal's youngest goalscorer when he netted against Wolverhampton Wanderers in a 5-1 win that December.
Arsenal have won only one league title (2004) and one FA Cup (2005) since he joined the club, while Barca have claimed three Champions League titles, five Spanish leagues and a King's Cup.
At international level, Fabregas has struggled to hold down a regular starting place in a Spanish team with a rich crop of midfielders, including Barcelona trio Xavi, Andres Iniesta and Sergio Busquets and Real Madrid's Xabi Alonso.
However, he scored the winning penalty in the Euro 2008 quarter-final shootout against Italy, a victory that is seen as a turning point in Spain's international fortunes.
He also played the ball through to Iniesta for his dramatic winning goal in last year's World Cup final.
"We have been clear that we didn't want Cesc to leave and that remains the case," Arsenal manager Arsene Wenger told the club's website.
"However we understand Cesc's desire to move to his hometown club and have now accepted an offer from Barcelona. We thank Cesc for his contribution at Arsenal and wish him future success."