The Roots' foray into becoming the coolest band in late night television began in March of 2009, when the Illadelphians signed on as the musical backbone of Jimmy Fallon's Late Night program. And in the nearly five years since, the group took Fallon from being the goofy, inoffensive and awkward SNL alum into one of the strongest entertainers in the business, largely due to The Roots' innovative and free-wheeling take on the old, established model. As the platform for a number of running sketches—Slow Jamming The News, Freestyling With The Roots—as well as the house band for any musical guests that came through, The Roots gave Fallon early breathing room by being entertaining and diverse, and grew with him into a full-on comedic and functional team.

So when it was announced last April that Fallon would be taking over Jay Leno's seat at the venerable Tonight Show—with the new show's first episode set to air tonight (Feb. 17)—it was natural that he would take The Roots with him to one of the most high-profile slots in late night. As the new show gets set to kick off, XXL takes a look back at some of The Roots' best musical contributions to the show, from Slow Jamming The News with Barack Obama to contributing to one of the greatest versions of Kanye West's "Bound 2" that has ever existed. Wise up. —Dan Rys (@danrys)

Slow Jamming The News With Barack Obama
It's not often that the President of the United States makes a late night television appearance, but it's not unheard-of, either. Then again, the appearance usually breaks down into little more than a softball-filled, mildly interesting Q&A section where Obama can legitimately defend his positions in a mostly controlled environment. It's not often that a late night host gets to refer to him as "The Preezy Of The United Steezy." But with The Roots laying down the background and donating their ineffable cool to Fallon, that's exactly what happened in April 2012 while the Prez was heating up his re-election campaign. And the Barackness Monster made for some wildly entertaining television.

Kanye West, "Bound 2" featuring Charlie Wilson and The Roots
With Kanye making the promotional rounds supporting Yeezus, Charlie Wilson's turn on "Bound 2" was making its way into mainstream conversations, and Kanye's lyrics were, as usual, at the center of the debate. But the remixed version Yeezys did with The Roots and a live choir on Fallon was one of the greatest performances in the show's history, with Wilson belting his heart out and 'Ye switching up lines like "Have you ever asked your chick for other chickens?" and "One good girl is worth a thousand chickens." Classic.

The History Of Rap
One of the best running segments on the show was Fallon's Justin Timberlake-assisted series "The History Of Rap." The four installments saw the host trading verses with Timberlake over The Roots' solid backing, running through classic hip-hop jams and connecting the thread of the genre through ten-second mashups. The four segments are tied together in one 20-minute clip, above, and it's crazy worth it to watch, for both the hilarity and the karaoke aspect. And the crowd, predictably, explodes as Timberlake leads them into "Empire State Of Mind." From Kurtis Blow to Snoop to Kanye, and everything in between, they cover just about all their bases.

Behind The Scenes, Episode One
March of 2009 came with a lot of nerves and a lot of questions, and Okayplayer documented the entire first show from behind the scenes. Watching Kirk, Quest and Tariq prep for their house band debut is as entertaining as it is interesting; five years later, it would be fascinating to see how things changed. As of right now, we've still got this little time capsule, where the band talks about 30 Rock's lack of toilets, beat-boxes their way through some last-minute preparations, and generally gets out their anxieties. Questlove's bow tie is, of course, the video's main star.

Method Man, "Protect Ya Neck" featuring The Roots
A pre-show performance that leaked out onto the Internet, Method Man stopped by the set as The Roots tore through one of Wu-Tang's classics, Black Thought and Mef going back and forth and trading off each other as only two of hip-hop's nicest MCs could do. The performance is a little understated, but is magical in one of those once-in-a-lifetime-type ways, especially when Meth powers through ODB's iconic verse. One of the dopest performances of the entire show.

Freestylin' With The Roots—And Alec Baldwin
One of the crew's best running segments—where they pick an audience member who gives them a topic, and Black Thought freestyles off the prompt—got an upgrade when the audience member in question was none other than Alec Baldwin, swinging through to promote the upcoming season of 30 Rock in 2012. Baldwin is, as usual, hilarious, and Tariq, as always, holds his own. The Roots pulling off a 1950s doo-wop song is not something to miss, even though the entire thing is just a ridiculous promo.

Drake Plays Beer Hockey
This one isn't especially Roots-heavy, though they do provide the carnival-esque backing track to this epic game of beer hockey. The first eight minutes is chock full of Drake Being Drake (and as it was a straight interview, we left that part out), but then things take a turn when Fallon invites the Canadian rapper to a game of air hockey with beer. It's worth checking out, for sure.

Clipse, "Grindin'" featuring The Roots
The Clipse were on the show ostensibly to promote their last album, Til The Casket Drops, but The Roots weren't gonna let Pusha and Malice get off without playing one of their classics. "Grindin'" was the result, and it's a good reminder that in 2010 Clipse were absolutely on top of the world rapping-wise. That minimalist Pharrell beat sounds dope with live instrumentation, and Black Thought brings the fire alongside them.

Kendrick Lamar, "Swimming Pools" featuring The Roots
"I want you to recognize that my Plan B is to win your hearts before I win a Grammy," Kendrick promises at the beginning of this performance. Still three weeks before K.Dot would light the hip-hop world on fire with good kid, m.A.A.d city, the performance is made all the better for that sense of anticipation, plus Questlove's vocals in the background. Pour up. Headshot. Sit down. Stand up. Pass out. Wake up. Faded. Faded....

Nas, "Nasty" featuring The Roots
Queens' finest came through to rock the stage with The Roots, and Nas delivered a high-energy performance of one of his best singles of recent years. God's Son always delivers.

Black Thought Raps About Halloween Candy
Yo, what is this beat though? Can we get this on the next Roots album? I would pay good money to hear Tariq rap about anything, much less some of the best candy to give out on Halloween. Another example of his lyrical dexterity, maybe, but definitely a highlight of his naturally effortless flow.

Black Star, "Little Brother" featuring The Roots
When the Black Star anniversary—which wound up sputtering without a true reunion album—was in full effect, Mos (or was it Yasiin?) and Kweli were back on top of the world, and this Aretha Franklin-inspired cut with The Roots was the collaboration that dreams were made of. If they ever did come back with a full reunion project, can we all chip in to make sure The Roots are their backing band? It makes too much sense to not happen.

Wu-Tang Clan, "6 Directions Of Boxing" featuring The Roots
"It is not easy to get these guys together in the same place at the same time," Fallon says by way of introduction, an understatement if there ever was one. Before the full-on reunion tour and the album that never was and may still never be, to be titled A Better Tomorrow, the Clan got together to perform a cut off RZA's Man With The Iron Fist soundtrack. While the summer that followed may have led to more rifts than reunions, it's still always a treat to see Shaolin's finest together on the same stage.

Eminem, "Won't Back Down," featuring The Roots
Em's big comeback with Recovery preceded his massive shows with Jay Z in Detroit and New York City, and were part of his ultimate redemption following five years of self-imposed exile. This performance was a re-affirmation of Shady's power and position in the game, even if a good chunk of it never made it past the television censors. A good showcase for the guitar prowess of The Roots, as well.