Madeleine Stowe has revealed for the first time her late father's battle with multiple sclerosis and how, as a child, she helped take care of him.

Stowe is sharing her story as part of biotech giant Genzyme's new campaign to educate and empower people living with MS.

"Back in the day, during my father's time there were no approved treatment options," she said in a video for the campaign, Lights, Camera, Taken Action on MS. "My earliest memory might have been 2, 3 years old and hearing he's not doing quite well."

Stowe said, "There wasn't a high level of anxiety around it. It was, 'Okay this is different, This is strange.' We were children…but there was this shadow. The shadow was MS. And we knew very little about it back in those days. There were no alternatives at the time. There was just the disease."

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The "Revenge" star was the oldest of three children.

"I became with my mother, my father's nursemaid," she recalled. "Sometimes I felt like I lacked mercy and I judged him when I shouldn't have, because I didn't fully understand. I thought sometimes his disease was actually something in his character. Of course that wasn't the case."

Stowe added, "I loved my dad very much, but I didn't know him. I remember feeling a very strong devotion to him. And more than anything I remember sticking by his side."

In the coming months, the 56-year-old actress will be touring the country, sharing her personal connection to the disease in a series of in-person and online events for people with MS and their loved ones.