Conan O’Brien will be the headliner at this year’s White House Correspondents Assn. dinner, scheduled for April 27.Fox News’ Ed Henry, the president of the WHCA, made the announcement this morning on Twitter. O’Brien last appeared at the dinner as the featured comedian in 1995, when Bill Clinton was president. The event is one of the more difficult gigs for any entertainer, as the gathering draws a mix of national media, Hollywood celebrity and D.C. elite. Perhaps the greatest challenge is that the headliner traditionally follows the president, who has his own jokes prepared. Recent headliners include Jimmy Kimmel, Seth Myers and Jay Leno.