Bruce Springsteen + Jimmy Fallon Cover LMFAO's 'Sexy and I Know It' -- Video

Last night marked the end of Bruce Springsteen Week on 'Late Night With Jimmy Fallon,' and while that's sad news for Boss fans, the final installment left plenty to savor all weekend long. New Jersey's favorite son played two new tunes and one old classic, but it was his cover of LMFAO's 'Sexy and I Know It' that's destined to go viral.

A sequel of sorts to his 2010 'Late Night' performance of Willow Smith's 'Whip My Hair,' the tune found Springsteen dueting with Fallon, who donned his hat and harmonica holder and once again did his uncanny Neil Young impression. Instead of dressing as his '70s-era self, as he did last time, Bruce rocked a sleeveless denim jacket and tied on a red bandana, reviving his 1985 'Born in the USA' look.

At one point, after singing the line, "Girl, I got that body / I work out," the 62-year-old rocker flexed his bicep, proving he's still pretty buff.

In his chat with Fallon, Springsteen discussed his style evolution and revealed how, back in the '80s, his and guitarist Little Steven Van Zandt's fondness for bandanas actually got them booted from Disney World.

Springsteen went on to perform 'Death to My Hometown' and 'Jack of All Trades' -- both from 'Wrecking Ball,' which hits stores Tuesday -- and his 1973 song 'E Street Shuffle.' On the final number, the Boss was joined by Fallon's house band, the Roots, as well as Rage Against the Machine guitarist Tom Morello, who appears on the new record and had guested on the previous two numbers.

Even Fallon, minus the Young garb, got in on the act, playing cowbell as the dozens-strong Roots Street Band worked up a brassy-heavy frenzy. Tough luck for any NBC staffers working late on the floor below Fallon's studio but good times for the rest of us.