- NEW: She talks to "Piers Morgan Live" on Tuesday night
- Harper, 73, is best known for her work on "The Mary Tyler Moore Show" and "Rhoda"
- She was recently diagnosed with a rare and terminal type of brain cancer
- "I have had a magnificent run ... I really look at my life as blessed," she says
(CNN) -- Sitcom star Valerie Harper might not have much time left on Earth, but she is determined to live life to the fullest.
"I just want folks to see me, that I'm OK, that I'm not suffering so far," said Harper, who was recently diagnosed with a rare and terminal type of brain cancer. "There may be pain. There may be a lot of things ahead, but whatever they are, they're ahead. They're not now."
Harper, 73, is best known for playing Rhoda Morgenstern on "The Mary Tyler Moore Show," and its spinoff, "Rhoda." Like Harper in real life, Rhoda was outgoing and had a smile that lit up the screen.
The actress told CNN's "Piers Morgan Live" on Tuesday night that she feels good and hasn't had any side effects from treatment.
Opinion: My open source cure for brain cancer
She said she is trying to live in the moment and had this advice: "Keep your chin up and don't go to the funeral, mine or yours or your loved ones, until the day of the funeral because then you miss the life that you have left."
Valerie Harper stopped by "Piers Morgan Live" on Tuesday in a prime-time exclusive. The actress, who played Mary Richards' best friend, Rhoda Morgenstern, on "The Mary Tyler Moore Show," recently revealed to People magazine that she has terminal brain cancer. The following is a celebration of some of TV's other most beloved sidekicks:
Vivian Vance's Ethel Mertz was always there to help her best friend out of a jam on "I Love Lucy." Unless, of course, she and Lucy Ricardo (Lucille Ball) were in a jam together -- in which case hilarity was certain to ensue.
Before becoming the breakout star of "Family Matters," Jaleel White's Steve Urkel was just the Winslow family's nerdy neighbor. Madly in love with Laura, Urkel routinely offered to help out her brother Eddie.
Andrew Koenig played "Boner" on a mere 25 episodes of "Growing Pains," but he left a lasting impression as the best friend of Mike Seaver (Kirk Cameron).
Jay Silverheels played faithful companion Tonto to Clayton Moore's Lone Ranger on "The Lone Ranger," which ran from 1949 to 1957 on ABC.
Steven Van Zandt portrayed Silvio, consigliere of Tony Soprano (James Gandolfini), on HBO's "The Sopranos." The Bada Bing strip club owner was known for always keeping his cool.
Gilligan (Bob Denver) was always there for his captain, the Skipper (Alan Hale Jr.), on "Gilligan's Island." Despite occasionally conking his "Little Buddy" on the head, the Skipper remained friends with Gilligan to the end.
Don Knotts played Barney Fife on "The Andy Griffith Show." Despite the occasional gaffe, the deputy sheriff was always there for Andy and Opie.
Burt Ward played Dick Grayson, also known as Batman's loyal sidekick Robin, on the 1966 series created by Bob Kane. Robin helped Bruce Wayne defend Gotham City on "Batman" until the show went off the air in 1968.
Jason Alexander's George Costanza plays Jerry's best friend on the hugely successful "Seinfeld," which ran for nine seasons on NBC.
On "The Many Loves of Dobie Gillis," Bob Denver played beatnik Maynard G. Krebs opposite Dwayne Hickman's Dobie Gillis.
Photos: Our favorite TV sidekicks
Harper: Remember me 'off the couch'
Harper's moments: Marriage, motherhood
News of Harper's illness was first reported by People magazine. It says she was told in January that she has leptomeningeal carcinomatosis, a condition in which cancer cells spread into the membranes that surround the brain and spinal cord.
Harpers' doctors say she could have as little as three months to live, People reported.
"The disease I have is quite a rare cancer and it is located in a limited area -- a very widespread area, but narrow. So a lot can happen if the cancer starts getting really aggressive, pressing on parts of the brain and causing me to lose either my speech or my ability to think, etc," Harper told Morgan.
But for now, she said, she is focused on putting one foot in front of the other, doing book tours, exercising, "just living my life."
An uncertain journey with brain cancer
"Death is out there for all of us," she said. "There's other ways to handle it than just sit on the couch and accept."
Harper previously battled lung cancer.
Leptomeningeal carcinomatosis, which is also known as neoplastic meningitis, affects approximately 5% of cancer patients, according to the Fox Chase Cancer Center in Philadelphia.
It is a difficult disease to treat because chemotherapy drugs often do not reach powerful enough concentrations in the membranes to be effective, the center said. Treatment can include radiation therapy and chemotherapy delivered straight to the spinal fluid.
"I have had a magnificent run -- the most wonderful husband in the world for 34 years, a great career," Harper said. "I really look at my life as blessed."
