The "Bloody Valentine" singer, whose real name is Colson Baker, showed off the unique look while posing for photographers at the Microsoft Theater in Los Angeles, shortly after teasing the move via Instagram Stories. "Special accessory for tonight," he wrote, alongside a video of someone from his team painting his tongue with a Q-tip.
Sonia Lee, who groomed the 31-year-old rocker for the awards show, told ET that the idea came from MGK's aides. He took things up a notch by painting his nails black-and-white, and accessorizing with rings.
Meanwhile, Adam Ballheim, MGK's stylist, told ET that the black tongue was "100 percent Colson."
"He always knows how to turn the dial up to 110 percent in the most rad way possible," Ballheim added of MGK.
In addition to the black tongue, MGK exposed his chest in an open, black Balmain suit. The look, Ballheim said, "really came from a place wondering what haven't we done for a major red carpet?"
"We've done bright colors, and really loud moments so instead of trying to one up those, we liked the concept of taking a very traditional idea -- the black suit with a white button down -- and putting the MGK spin on it," he said. "Balmain, of course, was perfect for that. It's at once classic and very modern, understated and a statement."
MGK attended the awards show with his girlfriend, Megan Fox, who turned heads in a sexy cut-out dress by Mugler and Jimmy Choo heels.
"Megan's amazing stylist Maeve also took that cue and found the most epic LBD in the history of LBDs," Ballheim said of the actress' stylist, Maeve Reilly.
The two packed on major PDA throughout the night, first with flirty pics on the red carpet and again inside the show before MGK accepted his award for Top Rock Artist. The rocker also won Top Rock Album for his latest album, Tickets to My Downfall.
The big win comes just weeks after a source told ET that MGK's relationship with Fox is stronger than ever, and that he would marry her "in a heartbeat." The pair first met in March 2020 on the set of Midnight in the Switchgrass.
"[Megan] is definitely in love, and having a great time with where things are at now," added the source. "She really takes her kids into consideration and knows that taking that next step would be a big adjustment, but it's not off the table."