The two-time Oscar winner posted on Facebook that he just completed treatment for alcohol addiction.
The Argo actor revealed that his struggle is "something I've dealt with in the past and will continue to confront."
Affleck's struggle with alcohol spans 15 years, with his first reported check in to rehab dating back to 2001.
"I want to live life to the fullest and be the best father I can be. I want my kids to know there is no shame in getting help when you need it, and to be a source of strength for anyone out there who needs help but is afraid to take the first step," he said in his post.
He recently stepped down from directing duty for an upcoming Batman film in February, but will continue to produce and star in the film.
In the post, Affleck acknowledges Jennifer Garner, with whom he announced plans for a divorce but has since seemed to be in reconciliation. He expresses his gratitude for the love from his family including his "co-parent, Jen, who has supported me and cared for our kids as I've done the work I set out to do."
Supporters voiced their renewed appreciation for the actor's fortitude in coming clean and sounded off on Facebook and Twitter.
There's more outpouring of love and support for Affleck continued on the next page.