BBC Sport's David Ornstein first reported the terms of the agreement, noting the Wales international's deal will see him earn £400,000 a week in Turin:
David Ornstein @bbcsport_david
Aaron Ramsey today signed pre-contract agreement to join Juventus in summer. 28yo penned 4yr deal after passing 2-part medical late Jan. Wales midfielder leaves Arsenal 30 June after 11yrs. Set to become all-time highest-paid GB player (basic salary), just over £400kpw #Juve #AFC
Football correspondent Kieran Canning explained how much Ramsey will cost Juventus over the four years:
Ramsey has been at Arsenal since joining the club from Cardiff City in 2008 but has been unable to agree a new contract and will leave as a free agent.
The 28-year-old has been an important player for the Gunners. He's won the FA Cup three times, scoring in two of the finals:
His loss will be felt by Arsenal, who struggled to bring in players in January. Manager Unai Emery admitted he was only able to make loan signings.
The club did manage to sign Denis Suarez from Barcelona on a temporary deal. His loan includes an option to sign him permanently in the summer, per BBC Sport.
Meanwhile, Ramsey's wages at Juventus will make him one of the highest-paid players in world football:
The Welshman is a quality option in central midfield who will bring flair and an eye for goal to Massimiliano Allegri's side:
Ramsey will also be hoping to add to his trophy collection during his time in Italy. Juventus have won the Serie A title for the last seven seasons and have completed a domestic double in each of the last four campaigns.