E! News, which first reported the marriage, said the couple wed over the past weekend.
The notoriously private Foster, 51, first acknowledged publicly that she is gay during a televised speech at the 2013 Golden Globe Awards, and referred to her "ex-partner in love" Cydney Bernard, with whom she has two sons.
She joked at the time that "I already did my coming out about a thousand years ago back in the Stone Age."
Hedison, 44, who had dated comedian Ellen DeGeneres about a decade ago, is also an actress. She appeared most recently in the former Showtime series "The L Word."