"It is my way, big mouth, you know me," she said.
Harper made the decision to go public with her cancer diagnosis in part because of her recent memoir, "I Rhoda." In it, the lifelong nonsmoker wrote she was free of the lung cancer she battled in 2009.
The day the book officially came out is the day she learned the cancer returned, but this time in the lining of her brain.
"I thought, 'I'm going to share this,' and because it's the brain, I wanted to do it quickly so I was speaking properly, you know, because you don't know what's going to happen. You just don't," Harper said.
The 73-year-old actress who brought the iconic TV character, Rhoda Morgenstern, into our homes on "The Mary Tyler Moore Show," and later on the spinoff, "Rhoda," knows her cancer is incurable "for now," she says.
But she is not letting the idea of death get in the way of life.
"I've been offered work, which is fabulous, and I'm going to do it," Harper said, adding that her doctors told her she can do everything that she has been doing.
"I am living a normal life, and I guess I wanted to let everybody out there know that," she said. "You're quite right about people having a picture of what having an incurable disease is, and I'd love to put a different face on that, and I think I have."
The many faces of Valerie Harper include a dozen characters she played in her one-woman show, "Golda's Balcony" about former Israeli Prime Minister Golda Meir and 12 people who cross paths with her.
Her face also graced the cover of last week's People magazine. She says it's true she could be gone in three months or a week - or maybe a year.
"There's also spontaneous remission where the body eats or kills the cancer cells out of nowhere," Harper said.
She said she talks to her cancer cells.
"I say, you know, 'What are you doing here? And you're stupid because you are eating the host. I can feed you if you stay low-key, but if you decide to attack me, that's so dumb because we're all going to go,'" she said with a laugh. "I mean, I have to keep my sense of humor."
Harper says her doctors have never seen a case like hers in 30 years of practice. An MRI has shown the cancer has not spread.