"I'm thrilled. Great, it's really great. I never thought that this is something I wanted," the Dalton, Ill., native, 49, told PEOPLE at Monday's Glee mid-season premiere party at Los Angeles's Bar Marmont.
"It's just the greatest thrill in the world to find somebody that you want to be with every day," she adds.
No date for the wedding has been announced, but Glee's new season premieres Tuesday night. Lynch plays the sharp-tongued coach, Sue Sylvester, whose mission is to ruin the McKinley High's glee club singers.
Reporting by JESSICA WEDEMEYER