U.S. President Barack Obama pokes fun at Facebook’s Mark Zuckerberg’s style

Mark Zuckerberg's hoodie and jeans uniform has become what pocket protectors and thick glasses were to the "Revenge of the Nerds" generation.

So when the co-founder of Facebook changes his look, it grabs headlines worldwide.

That's just what happened when U.S. President Barack Obama paid a visit to Facebook's offices on Wednesday. For the second time, Zuckerberg donned a tie and blazer for an encounter with Obama.

Obama joked about how uncomfortable formal attire must make the social-networking pioneer. You can watch his comments below.

PHOTOS: Zuckerberg dresses up for Obama

Zuckerberg first went formal for a meeting with the president and other technology leaders in February. Wednesday's conversation was an opportunity for Obama to reach out to American youth, promote initiatives aimed at keeping the U.S. competitive in the global economy and build momentum for the 2012 campaign.

Zuckerberg singled out Obama's Race to the Top education initiative as "one of the most under-appreciated and most important things (his) administration has done."

Zuckerberg has made education the focus of his first forays into philanthropy. In September, on the eve of the launch of "The Social Network," he donated US$100 million to public schools in Newark, N.J.

Obama received his own gift before leaving Facebook — a sweatshirt featuring the website's logo, "in case, for some reason, you want to dress like me," Zuckerberg said.

Maybe the president will return the respect and dress down when Zuckerberg visits the White House.