"Went to the most beautiful wedding I've ever experienced," Wilson tweeted. "Total Love, Jenna Fischer & Lee Kirk!"
It’s unclear if John Krasinski, the actor who plays Fisher’s onscreen hubby Jim Halpert on the NBC sitcom, also attended.
Fischer and Kirk began dating in January 2008 and became engaged during a European vacation last summer, according to Us.
This will be Kirk’s first marriage and Fisher’s second time down the aisle.
Fischer and director James Gunn divorced in July 2007.