A five-time Ballon d’Or winner spent two seasons playing alongside Pjanic in Turin.
The Bosnian midfielder was, however, to become the subject of a trade agreement involving Brazil international Arthur.
A South American midfielder is now in Italy, while Pjanic finds himself at Camp Nou.
The 30-year-old sought out advice from Ronaldo before heading to Spain, but a Real legend never suggested that he should steer clear of a team on the opposite side of a fierce Clasico divide.
Pjanic told Mundo Deportivo: “The opposite. When everything was done he told me that he was very happy for me, that I would be happy here because the game in Spain is very good and strong.
“It was bad for him that I was leaving Juventus, but he told me that he thinks I will have a lot of fun in a great team like Barcelona.
“Cristiano has been very professional at Juventus, he is a player who has shown many great things and who has been very important in the dressing room by setting an example for everyone.”
Pjanic is now preparing to line up alongside Lionel Messi at Barca.
He is accustomed to working with such talent by now, with a spell at Roma seeing him become a team-mate of Francesco Totti before moving on to Juve and eventually seeing Ronaldo join him at the Allianz Stadium.
“And with Buffon too!” Pjanic said of playing with modern day legends.
“The mentality is what is important and they are so unique. They've played for many years at a top level and to do that you have to be focused on your work, you have to love football.
“They always want to improve in all competitions, they are an example for everyone.”
Pjanic has had to shake off a bout of Covid-19 since securing a switch to Barcelona, but he is now very much part of the fold under Ronald Koeman and raring to get going.