Just when you thought James Corden and Neil Patrick Harris couldn't get more annoying.

Neil Patrick Harris interrupted James Corden during the opening of his show last night to challenge the 'Late Late Show' host to a Broadway riff-off to settle a dispute and figure out who is truly more Broadway.

This really wasn't a riff-off but more of an experiment in seeing who could be more irritating in a short space of time and it turns out that instead of cancelling each other out as one would hope a competition between the two would, their powers actually end up combining to become exponentially worse.