Ropp added, "He had to have a sober liaison that would bring him to set and that would bring him back from [the] set."
It is often common practice for a person working an outpatient recovery program to have a "sober escort" to help get them to "appointments with doctors, therapists, counselors, and support groups," according to Sunrise House.
The "Justice League" alum also spoke to People about the "The Way Back," which follows the story of a struggling alcoholic who has a chance at redemption while coaching his high school alma mater's basketball team.
"There are some things about this character I really could connect to -- being a recovering alcoholic, going through family strife, a divorce."
He added, "You try to bring your own life experience to the parts that you can use your imagination on the other parts."
In March of last year, Affleck opened up about about his struggle with the disease, telling Hoda Kotb on "Today" that it is a "lifelong struggle."
"Some people are really uncomfortable, it doesn't bother me to talk about alcoholism," Affleck said at the time. "Being an alcoholic, it's part of my life. It's something that I deal with. It doesn't have to sort of subsume my whole identity and be everything, but it is something that you know you have to work at."
"I had a problem and I really want to address it," he continued. "I take some pride in that...It is about yourself, your life, your family and people we encounter these kinds of hurdles and we have to deal with them."
Affleck had two other stints in rehab in 2001 and 2017.