The D are back! Self-proclaimed "greatest band in the world," the duo comprised of Jack Black and Kyle Gass have unveiled a comeback video for their upcoming album 'Rize of the Fenix.'

In the funny video, Black and Gass live two vastly different lives after their film, 'Tenacious D in The Pick of Destiny,' flops at the box office. But the two reunite in an epic hug and return to the studio only to realize they forgot how to rock! So what do they? Why, an awesome training montage, of course! Not only does good friend Dave Grohl help out, but The D even gets vocal lessons from Josh Groban himself! (Note: the video features some violence and NSFW language.)

It's also nice to see Val Kilmer take a bullet for Jack Black. Then again, it's just nice to see Kilmer do anything on screen these days. (Funny how the mighty have fallen.) But like a phoenix rising from its ashes, we can't wait to hear new material from the always hilarious Tenacious D. If you're not too familiar with band's awesome-ness, check out their "greatest song in the world" and our personal favorite 'Master Exploder.' Like the new video, they are a bit NSFW.