"There was a photo of your back tattoo that got a lot of attention," DeGeneres said after she and Affleck discussed his new Netflix film "Triple Frontier".
"It did, not so much positive," Affleck responded. DeGeneres followed up, calling it "a commitment".
As the "Gone Girl" actor started to explain, Ellen said that it was "rising from your a--."
"It's a phoenix, rising from my a**," Affleck acknowledged. "I was about to say it represents something really important to me, but maybe, just, we'll skip that.
"It's meaningful to me, I like it. It's something that I sort of kept private. It wasn't like I was sort of doing photo shoots or whatever. We didn't know the paparazzi was there so they got a picture of my tattoo and yeah the sentiment ran against," he said.
But despite criticism, the "Argo" star stood by the tattoo, adding: "I love my tattoo. I'm very happy with it."
In a March 2016 interview, Affleck had said the phoenix was "fake for a movie", but two years later when it was still there, another publication issued an article criticising the tattoo.