Michael J. Fox sat down with People recently, and opened up about the “darkest moment” of his life. The Family Ties actor, who went public with his Parkinson’s diagnosis in 1998, noted that the setback was unrelated to Parkinson’s.

He said that in 2018, a noncancerous tumor was found on his spine, and that it was causing terrible pain. The 59-year-old said: “I was heading for paralysis if I didn’t get it operated on.” However, surgery was risky.

The tumor “was constricting the spinal cord, so they had to be very careful in removing it so they wouldn’t do further damage,” he explained.

But he went forward, and began a rehab process, learning how to walk again. Then, putting the nightmare behind him, he went to Martha’s Vineyard with his family, and returned to NYC solo to do a cameo in a Spike Lee film.

He fell on the morning of the shoot and broke his arm. He said: “That was definitely my darkest moment. I just snapped. I was leaning against the wall in my kitchen, waiting for the ambulance to come, and I felt like, ‘This is as low as it gets for me.’ It was when I questioned everything. Like, 'I can't put a shiny face on this. There's no bright side to this, no upside. This is just all regret and pain.' “

He continued: “Optimism is really rooted in gratitude. Optimism is sustainable when you keep coming back to gratitude, and what follows from that is acceptance. Accepting that this thing has happened, and you accept it for what it is. It doesn't mean that you can't endeavor to change. It doesn't mean you have to accept it as a punishment or a penance, but just put it in its proper place. Then see how much the rest of your life you have to thrive in, and then you can move on.”

Fox added: “It’s not that I wasn’t sincere before, but my gratitude is deeper now, from having gotten through the darkest times.”

Fox’s fourth memoir, No Time Like the Future, is set for release November 17th.