What happens when two of the most likable guys in show business sit next to each other for a week? Oh, probably some impressions, some Milli Vanilli dance moves and just a lot of general charm spilling about everywhere.

Fresh off of hosting "Saturday Night Live" for the fifth time, Justin Timberlake is spending the week at "Late Night With Jimmy Fallon", performing new songs every night and, as Jimmy himself hinted, probably joining in for a sketch or two.

Watch JT break out his Jimmy Fallon impression on last night's show above and tune in all week for more.

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