Justin Timberlake Teases Super Bowl Halftime Show

Justin Timberlake is making sure he's lean and limber for next weekend's Super Bowl Halftime Show.

JT just posted a vid of himself doing some deep leg stretches during rehearsals for his highly anticipated gig during the big game next Sunday. While he doesn't provide much of anything as far as details for the show go ... you gotta imagine the singer plans on doing plenty of dancing.

Stretching video aside ... still no hints that Janet will be joining him onstage.