Gazzetta dello Sport says his new salary jumps to €6m plus bonuses - a minor increase on the previous €5.5m.
“It's an historic, unforgettable day," he told Juventus TV.
“For me, it's a dream come true. It's another signature on an important contract, and I owe it to the President, Fabio [Paratici], Pavel [Nedved], all my teammates, the fans and those dear to me.
“Juventus are my home. The signing of this contract proves once more how much I care about this shirt and how much Juve show me they care each year.
“I hope to make lots more appearances, score more goals and win more trophies."
The 32-year-old was also asked if this was the best period of his Juve career.
“Yes, in part thanks to the [captaincy] I was given by the club after Giorgio's (Chiellini) injury.
“My objective was to grow after last season. I can compare it to 2016-17, when I made the world top 11 and Champions League Final.
“Right now, the sensations are the same. Our objective is the Champions League Final.
“Today is November 19, my number is 19 and it's also my wife's birthday. I'll never forget this day."