Dave does Dave

It will be potentially the most embarrassing appearance on a talk show since Jonathan Ross asked David Cameron if he ever had sexual fantasies about Margaret Thatcher. Equally, if he pulls it off with aplomb there will be dividends. The prime minister is going to “do” David Letterman tonight. As I fly back over the pond from two weeks filming a US election-related Unreported World (7.30pm 2 November) Mr Cameron is in New York for the UN and a bit of soft diplomacy. But what will the yanks make of the two Daves across the chat show table?

It is tempting to think of Jon Stewart as the most risky talk show host in America but for my money Letterman still has the potential to do more damage. Stewart is a satirist, Letterman is an entertainer. While Stewart will stray into the serious quite regularly (although he never quite put one over Tony Blair in his famous 2008 appearance) Letterman is not out for a serious debate unless it’s something the American public is screaming about. So when he had Barack Obama on a couple of days ago in the middle of the uproar over a leaked video of Mitt Romney dismissing 47 per cent of American voters for not paying federal income tax he gave the President a platform to speak. I’m not sure if the majority of Americans could name or recognise David Cameron. There is no great controversy they will want to see him addressing so Letterman is going to have less to play with.

The host is generally courteous and teasing with politicians – inviting them to comment on popular myths. When Tony Blair went on he kept asking him about how thick George Bush really was Blair handled it well. When Boris Johnson appeared he was not quite the confident figure he cuts on British TV but he took the hair gags well and made the audience laugh. But David Cameron has neither Blair’s stature in America nor Johnson’s wit. And how he fares might also depend on whether Letterman treats him as the posh Englishman – somehow related to the Queen, married into the aristocracy and educated at England’s finest, etc.

The prime minister’s network of advisers, writers and friends like Michael Gove (who was a funny student debater in his time and had a brief career as a Channel 4 satirist on the ill-fated A Stab in the Dark) will no doubt be coming up with various lines for his appearance. This could go very badly. There is nothing more cringe-worthy than the man who thinks he is a wit but is only half right. One of the best things about David Cameron with Jonathan Ross was that he looked like he was enjoying it. I’d say the best thing he can do with Letterman is not use any pre-prepared lines, laugh at Dave’s jokes (but not necessarily agree with their thrust) and enjoy himself. It’s not like he can pull out now anyway, is it? I suppose there’s always that Twitter account to turn to for some feedback.

Follow @krishgm on Twitter.