People.com said Cohen and Fisher have been together for about eight years and are the parents of a 3-year-old daughter named Olive.
"We did it -- we're married!" Women's Day quoted Fisher as saying in an e-mail to friends. "It was the absolute best day of my life and in so many beautiful moments I missed you all so much. I thought of you as everything was happening, but Sacha and I wanted no fuss -- just us!"
Cohen has starred in the films "Borat," "Sweeney Todd: The Demon Barber of Fleet Street" and "Bruno."
Fisher's film credits include "Wedding Crashers" and "Confessions of a Shopaholic."