As Jimmy Fallon pointed out last night (Dec. 6) on 'Late Night,' he's "so lucky" to have house band the Roots on the show every night. They're a versatile crew that can play with just about anyone, but they're also pretty great on their own.

Since yesterday saw the release of the Roots' 13th studio album, 'Undun' -- a conceptual work that includes forays into Impressionist French classical music -- hip-hop's greatest big band grabbed the spotlight and performed two new songs -- videos below.

First up was 'Tip the Scale,' which featured soulful vocals from guest Bilal. It begins as an R&B-flavored slow jam -- all keyboards, strings and the measured rhyming of Black Thought -- but morphs into something altogether different.

There's an orchestral interlude, followed by an avant-jazz freakout, punctuated by the spastic hammering of pianist D.D. Jackson. Bandleader Questlove's drum riser moves into the foreground, then pulls back toward the end of the epic song, which ends in the same laid-back style it begins.

Bilal stays on for the second number, 'TheOtherSide,' offering a mighty Prince-like shriek after an instrumental jam that finds guitarist Captain Kirk Douglas taking charge like the intergalactic Spartacus his pop-culture mash-up of a stage name suggests.

Yep, Fallon is pretty lucky.

Watch the Roots Perform 'Tip the Scale'

Watch the Roots Perform 'TheOtherSide'