He sang Creep by Radiohead.
It's Ken Jeong! Koren-American Hollywood actor and recent panelist on Fox's 'The Masked Singer'.
After unmasking himself, he introduced himself and shared that his Korean name is Jeong Kang Jo. Backstage, he explained that he decided to appear on “The King of Mask Singer” because his mother is a great fan of the show. He also said, “This was the first time I got to sing on an official stage that isn’t a comedy show. I was always the one to guess who’s behind the mask, but now that I’ve tried singing as a contestant, I’ve come to understand how they feel. My wife and kids were very excited that I would be singing behind the mask of a pig’s face.”
source: MBCentertainment, soompi, tvdaily
Did you guess right?