Forget the Heisman Trophy ... get Ole Miss QB John Rhys Plumlee a Grammy -- 'cause the dude can SAAAAAAAAAANNNGGG!!!
Here's video of the Rebels star at the 2019 C Spire Conerly Award ceremony Tuesday in Mississippi ... taking ALL of the shine away from the other award finalists.
It's unclear why JRP stepped up to the piano ... but we're all sure as hell glad he did -- 'cause the 18-year-old tickled the keys and belted out "Drops Of Jupiter."
And, yeah, we're all swooning!!!
As for what went down after Plumlee's impromptu concert .