Michael J Fox was "surprised" by the reaction to his Parkinson's diagnosis

Michael - who has become a strong advocate of Parkinson's disease research - shared: "It was a great surprise to me that people responded the way they responded.

"They responded with interest, in the desire to find an answer to the the disease, and then I saw that as a great opportunity. I didn't get put in this position to squander it."

The Hollywood star has helped to raise a huge amount of money for research into the disorder.

But Michael doesn't focus too much of his attention on his own efforts.

He told 'Entertainment Tonight': "I don't spend a lot of time on that.

But I am grateful when people express to me that it means something, [that] means a lot to me. But I don't think about it. I don't get up and go, 'Oh, I'm Mr. Impact!'"

Michael admits there "are days that suck" with Parkinson's.

But he generally tries to remain philosophical about his situation.

The 'Back to the Future' star said: "I've had Parkinson's for 30 years ... I think it's part of my life, it's what and it's who I am and it's a struggle sometimes. I'm not gonna lie, it's really hard to get up and get ready and get out in the world [some days]. There are days that suck.

"[But there's] just an understanding that I will get through it. At any moment, you have a choice: I cannot get through this moment or I can get through this moment."