The man who became an Internet sensation for his campy, wordless rendition of Russian song is in hospital with severe brain damage.

Russia Today reports that folk singer Eduard Khil, better known as the 'Trololo guy' after a vintage video of him singing I Am So Happy to Finally Be Back Home went viral on YouTube in 2010, is in a coma with irreversible brain damage following a stroke.

Surgery could save his life, doctors say, but even if he survives, there's no guarantee he'll ever recover.

The singer rose to fame in his home country during the '60s, but became a worldwide phenomenon two years ago when the Trololo video hit YouTube. It's since been viewed more than 12 million times, inspired dozens of imitations and sparked an online petition asking the 77-year-old singer to go on a world tour.

In a 2010 interview with Radio Free Europe, Khil said he became aware of his newfound fame when he heard his 13-year-old grandson humming the tune.

"My grandson, Eduard Junior, told me, 'Grandpa, everyone knows your song on the Internet - all around the world, in Japan, in England, in America. They're even selling T-shirts,'" Khil said.

The original Trololo song has lyrics about a man riding his horse across America to his sweetheart, but they were deemed to racy for Soviet censors, so Khil sang the song using random syllables and sounds.