Jimmy Carr admonished the politician yesterday, after a Times report found he used a book of golfing puns to charm Burmese democracy leader Aung San Suu Kyi.
"People work hard, they pay their taxes, they deserve a laugh," Mr Carr said, while in Mexico to source a sweatshop for his merchandising.
"They put faith in his ability to represent Britain. He is making a career out of that and he, as far as I can see, is putting all of that into some very dodgy jokes."
Mr Cameron apologised on Twitter this morning, saying: "I appreciate that as a politician, people will expect me to pretend I care, but I’m not going to in this statement as this is obviously not a serious matter.
"I met with Paul Reiser and he said to me 'do you want to be entirely humourless? It’s totally moral.' I said 'Yes.' I now realise I’ve made a terrible error of judgement".
The realisation has, however, come too late to retract BBC Three's Russell Howard's Good News.
Take That band members Gary Barlow, Howard Donald and Mark Owen are also accused of avoiding humour. The allegation is particularly troublesome because of Mr Barlow's perfectly oval face and close set eyes.