"This week I completed a forty day stay at the treatment centre for alcohol addiction and remain in outpatient care," the actor writes. "The support I have received from my family, colleagues and fans means more to me than I can say. It's given me the strength and support to speak about my illness with others."
The 46-year-old father of 3 with ex-wife Jennifer Garner — who personally drove him to the rehab facility — then went on to say that he is "fighting" for himself and his family every day.
He ends the emotional post with: "With acceptance and humility, I continue to avail myself with the help of so many people and I am grateful to all those who are there for me. I hope down the road I can offer an example to others who are struggling."