Justin Timberlake's been rehearsing his ass off for the Super Bowl LII halftime show, and TMZ has the first video ... which gives you a sneak peek of what's about to go down.
Sooo, HERE'S YOUR LAST WARNING ... SPOILERS AHEAD!!!
Sources inside rehearsal tell us JT did 4 run-throughs, just on Thursday. We're told one was a dress rehearsal that was taped for emergency ... just in case anything happens to JT and he can't perform.
This video is from one of his Thursday sessions, and one thing's for sure .