The Emmy-nominated actress, 28, met the Saturday Night Live funnyman when she made a guest appearance on the hit U.S. sketch show and Armisen proposed in January 2009 after a whirlwind romance.
They wed in October (09) - but have since parted ways, reports America's Life & Style magazine.
A source tells the publication, "Fred and Elisabeth separated in May.
"Fred is currently in Portland, Oregon on the set of his new series Portlandia. Elisabeth is in L.A. focusing on her career and spending quiet time with friends."
The marriage was Moss' first, while Armisen, 43, was previously married to British singer Sally Timms. They split in 2004.