I guess James Corden always wanted to be in a boy band, so he just forced himself into performing at a Backstreet Boys concert in Vegas. At first BSB was hesitant, but eventually, they taught him the moves because he already knew all the words to their songs.
Finally, he was ready to take the stage and he was, well, larger than life. That is not a good thing. But at least The Late Late Show host is a one song and done type of guy. Because I do not think the audience would have handled any more than that. Could you have?