Those taking the PCH to catch Friday’s SLS better be prepared for Machine Gun Kelly — Nyjah Huston tells TMZ Sports he’s expecting MGK to perform a wild show at the Street League Skateboarding event!!

The competition officially kicks off at the Santa Monica Pier in just a few hours — at 1:30 PM PT, to be exact — and while most fans will come to watch Huston and other skaters throw down tricks … the Olympic bronze medalist told us they’re going to get a treat from MGK once they arrive as well.

Huston said the “my ex’s best friend” crooner will belt out a few songs … before explaining to us, “I heard they actually have a whole, like, special way he’s going to perform.”

The entire event looks like it’ll be must-see, as Huston called the location a straight up “legendary skate spot.”

Plus, he told us he can’t wait to flip his board by the Pacific Ocean — considering as a California-native, it’s basically his backyard.

“It’s going to be a great vibe,” Huston told us. “I love that it’s a free event — just invite all the fans to come out and have a good time.”