"Standing for the vulnerable should be something that everybody can get behind," he stated.
Watson said it was encouraging to see the up to 100,000 attendees who came out for the cause.
"People of all ages, all ethnicities, you have Democrats, Republicans all joining us for life," he told the "Friends: Weekend" hosts.
"And so, every time I have an opportunity to go, it is kind of like being in a huddle and everybody getting together encouraging each other before we go out and continue to fight for life," Watson said.
Watson is currently producing a documentary on the issue called "Divided Hearts of America," which is set to release later this year.
He said that his journey through the film is "getting to the issues -- getting to the truth."
"What is abortion? What are the implications if we don't deal with this in the correct way?" he asked. "It's important we are able to talk about these issues. I believe this issue is the issue of our day that is tearing our country apart."