The couple married sometime before Chadwick's death in August 2020, four years after he was diagnosed with stage four colon cancer.
Denzel has produced "Ma Rainey's Black Bottom", which was the last film Chadwick Boseman worked on.
"It's fascinating that nobody knew," Denzel said of Boseman's private battle with cancer in an interview with CBS, reports ew.com.
"Well, credit to him; he kept it to himself. It was nobody's business. He was there to deliver and he delivered. Certain members of his team knew. His wife was there. They weren't even married yet," he shared.
"And I used to watch how she took care of him, and I actually said to him, I said, 'Man, you know, you need to put a ring on that finger, because she kept her eye on him and she watched him. And I'm like, 'Man, she loves that guy.' You know, but I didn't know what we know now," he added.
Chadwick and Taylor had been romantically linked since 2015. They got engaged in October 2019.
While announcing his death in August on the late actor's social media accounts, his family confirmed that the couple had secretly married.