Written byRajdeep Saha
The Catalans say Arthur's fee will rise to €82m (£75m) after an initial payment of £66m.
Both players will remain with their respective clubs till the end of the 2019-20 season.
The 30-year-old Pjanic will sign a contract with Barcelona for the next four seasons, until the end of the 2023-24 season, with a buy out clause of 400 million euros.
Pjanic is a complete mid-fielder and is suitable in both attacking and defensive roles in the position.
He is blessed with excellent free kick taking abilities as well.
Pjanic started his career in Ligue 1 with Metz in 2007 and scored five goals in 38 appearances.
He moved to Lyon a season later and amassed 16 goals in 121 appearances.
Pjanic moved to Roma in 2011 and made his presence felt with 30 goals in 185 appearances.
He sealed a move to Juventus in 2016 and has 22 goals in 171 games.
Juventus get a promising mid-fielder in the form of Arthur.
He had joined Barca in 2018 from Gremio.
The Brazilian mid-fielder has played 72 games for Barca until now in all competitions.
He has four goals in two seasons at the club.
Arthur, who won La Liga in 2018-19, will hope to establish himself in Turin and be a vital cog for the side.
According to a report in Sky Sports, Juventus manager Maurizio Sarri is keen to build the mid-field around Arthur, just like they way he utilized Jorginho at Napoli and Chelsea.
The Turin club has also offered Arthur a much better package as compared to his current deal at Barcelona.
Juventus are believed to have offered £4.5m (€5m) a year to the player.
As per Sky Sports, Arthur flew into Turin on Saturday night just hours after playing as a late sub for Barca against Celta Vigo in La Liga.
He subsequently underwent medical exams on Sunday and signed a five-year contract before flying back to Catalonia to resume training.
He will hope to make his presence felt in Barca's crunch clash against Atletico Madrid tonight.
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