Jonny Fairplay -- My Grandma Is REALLY Sick ... For REAL This Time

"Survivor" villain Jonny Fairplay -- the guy who lied about his grandma dying to get an edge on the show -- is currently racing to visit his grandmother in a Virginia hospital after he learned she was having chest pains.

Jonny tells TMZ ... "My grandmother went to prime care in Danville ... she will be kept at the hospital for overnight observation."

Back in 2003, Fairplay pulled off the most evil trick ever ... when he convinced a friend to LIE to "Survivor" producers and tell them his grandmother passed away during production. The plan worked and bought Fairplay enough sympathy to get him further along in the game.

Now, Fairplay says he's hopeful grandma will be OK ... telling us, "She's no longer having the chest pains after they gave her some medication but they're checking to see what happened."