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WASHINGTON (CBS) -- It's one of the toughest audiences for a comedian: the White House Correspondents' Dinner. But Conan O'Brien is returning, nearly 20 years after his first appearance.

Conan O'Brien is headed to Washington. In April, the comic will headline the White House Correspondents Dinner, an annual gathering that brings together members of the press, Hollywood actors, and Washington power brokers.

It's also an opportunity for the president to take public shots at his rivals. In 2011, President Obama said, "No one is prouder to put this birth certificate to rest like the Donald so now he can focus on bigger issues at hand- like did we fake the moon landing, what really happened at Roswell and where are Biggie and Tu-Pac."

Comedians have entertained the crowd before, with Jay Leno, Craig Ferguson, and Jimmy Kimmel all making appearances in recent years. The tone is mostly lighthearted with an occasional bite at the jugular. Jimmy Kimmel said last year, "Mr. President, remember when the country rallied around you in hopes of a better tomorrow? That was hilarious."

But as with all White House events, choosing the headliner is as carefully planned as the guest list itself. Politico Editor in Chief John Harris says, "Conan O'Brien who's done this dinner before, he knows he's got a very tall order in front of him to be funny, but be funny in a way that people don't say crosses the line."

That's what happened in 2006, when Stephen Colbert delivered a searing roast of then president george W. Bush. Colbert said, "To sit here at the same table as my hero George W. Bush, to be this close to the man. I feel like I'm dreaming, somebody pinch me. You know I'm a pretty sound sleeper that may not be enough somebody shoot me in the face."

O'Brien has been at the podium before in 1995. He was a fresh face on the late night circuit. He said in 1995, "Finally I have an announcement for those you watching tonight's event live on C-SPAN, for God's sake it's Saturday night."

Nearly twenty years later, organizers can only hope he'll poke some fun without poking anyone in the eye.