The former star of 1960s TV series Gomer Pyle, U.S.M.C. was diagnosed with aortic stenois - a narrowing of the aortic heart valve - earlier this year (12) and he's due to have a replacement operation at a Honolulu, Hawaii medical centre on 29 May (12).
The 81 year old tells the National Enquirer, "It's about a three-hour surgery, and if all goes well, I should have to spend only one night in the hospital. This is less invasive than having to open my chest, but anything that has to do with the heart area is always a bit scary, especially at my age."
The actor has been suffering with declining health in recent years - he received a liver transplant in 1994 and last year (11), he was hospitalised with a throat infection.
The Andy Griffith Show star's latest crisis will force Nabors to bow out of his annual Memorial Day tradition (28May12) of performing his hit tune Back Home Again at the Indianapolis 500 car race, a ritual he's kept since 1987.