O'Hara, 73, was a theater director and artist born in Connecticut. She founded the New Thalian Players in Manchester, New Hampshire, where she produced and directed 50 plays over the last 25 years.
Silverman opened up about one of the many lessons she learned from her mom in an ET interview last September.
"One time, she said, 'Sometimes all you have to do is be brave,'" she told ET as she wore overalls to honor her mom. "Just meaning [that] sometimes you just have to exist through things and they pass or you get to the other side."