The prank by Washington Journal, on the US political channel C-SPAN, is being circulated online, showing a viewer, Dan, who purports to come from Portsmouth, New Hampshire, feeding Gregg a bunch of nonsense about understanding what he is “going through at the moment”.

Dan then unleashes a highly awkward question – about presidential candidate Mitt Romney’s penis –the same Mitt Romney that Gregg is on the show to support.

The ensuing embarrassment is breathtaking.

The anchor apologises to Judd, who looks stunned, then chuckles “I want to make sure I heard him right”.

The Washington Journal is a long-running programme which regularly sees viewers from all walks of life call in and ask questions of its guests.

Watch the video here:

And here’s a prank on Sarah Palin to get your funnies going: