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Kristen Johnston, known for her portrayal of a member of an alien family on the 90s' sitcom "Third Rock From the Sun," recently revealed to the world a very human weakness: she is an alcoholic.

So bad was her addiction, Johnston wrote in her memoir "Guts," that even after a combination of alcohol and pills caused her stomach to tear open, she still hid her struggle from her doctors.

It was a conversation with a friend, Johnston told "20/20's" Elizabeth Vargas, that finally put her on the road to sobriety.

"I called her and said I'm … I'm worried about my drinking, and she said, 'Well, just go get it dealt with,'" she said. "It just made it seem like I got to get my nails done, I got to go to rehab. You know? …It sounds so stupid, but it just sounded like something you could deal with."

"Just the way she said it really saved me - saved my booty," Johnston said.

Learn about Kristen Johnston's experience at a rehabilitation facility and more on "20/20: Intoxication Nation" Friday at 10 p.m. ET.