Barcelona have completed the £15m signing of Arsenal's Belgium international defender Thomas Vermaelen on a five-year contract.
The 28-year-old passed a medical on Saturday and was presented to fans and media at the Nou Camp on Sunday after finalising the deal.
"Coming to Barcelona is a dream move - it wasn't a difficult decision at all," the centre-back said.
Vermaelen joined Arsenal from Ajax for £10m in 2009 and made 150 appearances.
Barcelona's new signing said: "I feel ready to play here. I think I can offer a lot to this club.
"There's a lot of competition here but I'm very excited. It's up to me to show what I can do - it'll be a challenge for me."
Vermaelen had been a target for Manchester United but they ended their interest after refusing Arsenal's demand to receive a player as part of the deal.
Gunners manager Arsene Wenger confirmed ahead of Sunday's Community Shield match against Manchester City that he would be looking for a replacement defender.
He told BT Sport: "At the moment it is a possibility that someone comes in to replace Thomas Vermaelen. I can't tell you who!"
|Thomas Vermaelen's career|
|Previous clubs||Arsenal, Ajax, Waalwijk|
|Club honours||Dutch league (2004), Dutch cup (2006, 2007), Dutch Super Cup (2006, 2007), FA Cup (2014)|
Vermaelen was troubled by a series of injuries and lost his place at centre-back last season as Wenger favoured Per Mertesacker and Laurent Koscielny.
His form and fitness meant he made only 21 appearances in all competitions last term.
Vermaelen added: "I want to put the injuries I've had behind me and look to the future. My aim is to play in lots of games and help the team.
"I am keen to get started and I know the demands here are really testing."
Vermaelen becomes Barca's second centre-back signing this summer after Valencia's Jeremy Mathieu, their first recruit in that position since 2009.