Barcelona president Joan Laporta said that signing rangy striker had been a long-standing dream of the club.
"Thierry Henry is a player we've been after for many years and now he's here," said Laporta.
"Johan Cruyff wanted to sign Thierry Henry when he was a young player. When I was elected president in 2003 I wanted to sign him, we also wanted to get him last year and today it is a great pleasure to finally see him here.
"He is one of the best players in the world and given his quality, experience and commitment he comes to Barcelona at the perfect moment."
Henry was presented with the number 14 shirt, the squad number he had at Arsenal and the same as that worn by Barcelona great Cruyff.
Henry shows off his new shirt during his unveiling.
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