Justin Timberlake celebrated St. Patrick’s Day by closing out the SXSW Festival in Austin, Texas. The show was supposed to be top secret, but the news that Justin Timberlake would be there leaked so fast, we wouldn’t be surprised to learn that some fans heard about it before the pop star did.

The South by Southwest is notorious for bringing out huge secret acts sometime during the celebration, and often celebrities play on that by dropping clues and hints to their fans somewhere along the way. But this time, fans were told all but what time to show up.

Nearly as soon as JT was booked to play the festival, the Austin Police Department started preparing for it, bringing on additional security and making sure they’d have the grounds and city properly covered. During those preparations, some members of the security team leaked the news that the additional forces were needed because JT was coming into town to perform. But fans didn’t have to hang around the Austin P.D. to know that one of their favorite superstars was coming to town.

That’s because JT’s crew had littered the venue Coppertank Events Center, where the show was held, with ads for his newest project MySpace. And if that wasn’t enough, just around the corner from those ads, the words “Secret Show” were written on a wall in the star’s characteristic typeface.

Although the show probably could have been kept under tighter wraps, JT pulled the show off beautifully. Mostly playing songs from his album that’s about to be released, “20/20,” he also brought in some favorites from his other solo projects, “Justified,” and “FutureSex/LoveSounds.” What might have surprised fans most was when JT broke out into a cover of INXS’ “Need You Tonight.”

In other JT news, he also recently confirmed a rumor that had been floating around about his album “The 20/20 Experience.” The album that’s about to be released is just the first half, with another album due out afterwards.