Italian champions Juventus agreed to buy Arsenal captain Patrick Vieira for 20 million euros (13.7 million pounds) on Thursday.
"Arsenal Football Club can confirm that terms have been agreed for the transfer of Patrick Vieira to Juventus," the London Premier League club said in a statement.
"At this stage, Patrick is now finalising his personal terms and conditions with Juventus."
Vieira, 29, was the core of Arsene Wenger's Highbury side which have won three league titles and four FA Cups under the French coach.
Vieira told Arsenal's website: "When you spend nine years at the club, like I did, it is a difficult decision to leave.
"But in the end you have to make a choice for your future. It was a very difficult decision, but I am happy with it.
"I made the decision to leave because I felt it was time for me to have a new challenge. But that does not mean I was unhappy or that I was having a problem at Arsenal.
"I can go with my head held high. I did my best every day in training and in every match," he said.
Vieira had been closely linked with moves to Real Madrid in the past two close seasons and said in May he wanted to see out the last two years of his contract with Arsenal.
VIEIRA REUNITED
His move will re-unite him with Fabio Capello, current manager of Juventus but formerly boss of AC Milan when they signed Vieira in November 1995 from Cannes.
Juventus said his fee would be paid in three instalments over two years, with an initial 10 million euros being followed by a further five million euros in July 2006 and July 2007.
A 1998 World Cup winner and Euro 2000 winner with France, Senegalese-born Vieira has also been one of English football's most consistent performers since making his debut in September 1996, shortly before Wenger's formal arrival at the club.
His last act in an Arsenal shirt was lifting the FA Cup in May after the penalty shootout defeat of Manchester United in the Cardiff final. Vieira scored the final spot kick.
"Patrick was a great player for us, one of the greatest in the club's history and I feel I had a special relationship with him because I made him come here," Wenger said.
"I think his impact, not only at Arsenal but in English football overall was just tremendous."
Vieira started his Arsenal career as a creative player but following the departure of compatriot Emmanuel Petit, he became increasingly defensive, often shoring up the Arsenal backline.
He was sent off 10 times under Wenger and had a long-standing feud with United's captain Roy Keane which made United v Arsenal games the highlights of the English season.
Turin-based Juventus have a long and successful tradition of signing French internationals, beginning with another midfielder, Michel Platini, who was the lynchpin of the team during the mid-eighties.
Vieira is the sixth member of France's 1998 World Cup-winning squad to sign for Juve after Zinedine Zidane, Didier Deschamps, Thierry Henry, David Trezeguet and Lilian Thuram.
Thuram and Trezeguet are still at the club and feature in the club's first-choice lineup as does another French international, defender Jonathan Zebina.