WASHINGTON -- Irish Prime Minister Brian Cowen was just a few paragraphs into an address at a St. Patrick's Day celebration at the White House when he realized something sounded way too familiar. Turns out, he was repeating the speech President Barack Obama had just given.

Cowen was set to speak twice at the White House on Tuesday night because there were two different parties going on at the executive mansion. No matter -- he would give the same speech to the two different audiences.

But Cowen was 20 seconds into his second address when it dawned on him that he was giving word for word the speech that Obama had just read from the same teleprompter.

Cowen stopped and looked back at the president to say, "That's your speech."

Obama laughed and returned to the podium to offer what might have been Cowen's remarks. In doing so, President Obama thanked President Obama for inviting everyone over.

Earlier, the president claimed an Irish ancestry to Ireland's leader and joked to Congress that his genealogy could have helped him as a once-unknown Chicago politician.

White House fountains and sparkling wine both ran green as Obama courted Ireland's prime minister and political leaders from Northern Ireland. As Obama sought to tamp down violence in Northern Ireland, he announced Tuesday a key campaign backer Dan Rooney, owner of the Pittsburgh Steelers football team, as his choice to fill the post of U.S. ambassador to Dublin.

"Not all Americans are Irish, but all Americans support those who stand on the side of peace and peace will prevail," Obama told Prime Minister Brian Cowen in the Oval Office, praising the two countries' deep ties.

On tap for the evening's festivities -- which Obama described as "rambunctious" to East Room guests -- was green sparkling wine from a California vineyard.

The White House cocktail reception featured Pulitzer Prize-winning poet Paul Muldoon from Northern Ireland and Maggie McCarthy, a traditional Irish dancer and musician from Cork, and the vocal group Celtic Thunder. The Shannon Rovers, the official pipe band of Chicago's St. Patrick's Day festival, also were set to perform.

Obama joked about the free-flowing bar and warned his guests not to wear lampshades on their heads in front of the cameras. He later went off his remarks to get laughs about Ireland's popular stout.

"Guinness tastes very different in Ireland," Obama said. "It is much better. You guys are keeping the good stuff for yourselves."