In big intro of running-mate Ryan, Romney's tongue slips

Republican U.S. presidential candidate Mitt Romney arrives to introduce U.S. Congressman Paul Ryan (R-WI) as his vice-presidential running mate during a campaign event at the retired battleship USS Wisconsin in Norfolk, Virginia August 11, 2012.

NORFOLK, Virginia (Reuters) - The stage was set on Saturday for Republican presidential candidate Mitt Romney's big introduction of his running-mate Paul Ryan, when Romney's tongue let him down.

"Join me in welcoming the next president of the United States, Paul Ryan," a beaming Romney told an energized crowd in Norfolk, Virginia, with the retired battleship USS Wisconsin as the backdrop.

After he walked off stage, Romney's wife Ann immediately told him he had made a mistake, prompting him to return to the podium to correct it.

"Every now and then I'm known to make a mistake. I did not make a mistake with this guy," he said at Ryan's side, then telling the crowd that the Wisconsin congressman was "going to be the next vice president of the United States."

Romney's flub comes after his gaffe-filled tour of Europe during which he offended the British by questioning their readiness to host the Olympics and the Palestinians by suggesting they were culturally inferior to the Israelis.

Apparently, the president-vice president slip-up is a fairly easy one to make.

During President Barack Obama's first joint rally with Joe Biden in 2008, Obama told an Illinois crowd, "Let me introduce to you, the next president — the next vice president of the United States of America: Joe Biden."

The campaign team of John McCain, then the Republican presidential candidate, quickly pounced on the mistake to suggest that Biden, a veteran Delaware senator, might wield the real power in an Obama administration.

(Reporting by Jason Reed; Writing by Vicki Allen and Karey Wutkowski; Editing by Jackie Frank)