"I am shocked and devastated by Jim's passing," Falco says in a statement. "He was a man of tremendous depth and sensitivity, with a kindness and generosity beyond words. I consider myself very lucky to have spent 10 years as his close colleague."
The Sopranos racked up Emmy awards for its fictional portrayal of the dysfunctional New Jersey crime family, with Gandolfini and Falco at its emotional core.
In real life, Gandolfini leaves behind his wife Deborah, son Michael – who reportedly found the actor still alive in his Rome hotel room Wednesday – and infant daughter Liliana, 9 months.
On Thursday, Falco acknowledged both his real-life family and the one he forged on the groundbreaking HBO show.
"My heart goes out to his family," said Falco, "as those of us in his pretend one hold onto the memories of our intense and beautiful time together. The love between Tony and Carmela was one of the greatest I've ever known."