She said: "I never felt right in my body. I loved Halloween as I could dress up as a guy.
"[When I realized I was gay] my heart sank and I thought, 'No one can ever find out.'"
Jane – who is best known for playing Sue Sylvester in 'Glee' – also recalled her battle with alcohol earlier in her career, admitting she rarely felt good about herself as she was so filled with shame about her sexuality.
The actress – who joined alcoholics anonymous when she was 31 - added in an interview with the Daily Mail newspaper: "I drank every day since my senior year of high school just to get a buzz.
"I only felt good about twice in that time, but I was chasing a thrill.
"I was lonely and, even when I was out as a gay person, there was so much shame in it still.
"I never got as far as thinking about suicide, but it wasn't a good time."
'Glee's' Jane Lynch relied on the US Postal Service to tell her parents she was gay
Jane Lynch's biggest regret is having an affair with her friend's lover