Post Malone's gone country, and it's challenging "traditional country stereotypes," according to one music expert.The star's genre shift landed him five of eight Grammys nominations. The artist is up for best recording package with his album "F-1 Trillion," and best country album. His song featuring Morgan Wallen, "I Had Some Help," was nominated for best country song and best country duo/group performance. Meanwhile, the rapper's country collaboration with Beyoncé, "Levii's Jeans," was nominated for best pop duo/group performance."F-1 Trillion" also features a handful of big-name country artists, including Wallen, Dolly Parton, Tim McGraw, Blake Shelton, Brad Paisley, Chris Stapleton, Lainey Wilson