In the past two weeks, the US comedians Jimmy Kimmel and Sarah Silverman - partners in real life - have been engaged in what could loosely be termed “Jimmy Kimmel and Sarah Silverman's A-List Sex-Off”. Via the largely disregarded medium of the comedy song, Kimmel and Silverman have registered more than 8 million hits in their battle for humour supremacy, bringing workplaces all over the world grinding to a halt as entire offices suspend labour to watch them.

In a nutshell, on the occasion of Jimmy Kimmel Live!'s fifth birthday, Silverman presented her boyfriend with a video entitled I'm F***ing Matt Damon - a heartfelt duet between Silverman and the intent-looking Damon, which included Damon singing “I'm sorry but it's true ..On the bed/On the floor/On a towel by the door.”

Last week, Kimmel revealed his retort - I'm F***ng Ben Affleck. Over three minutes, the video doubles in its insanity, in-jokes and celebrity roughly every 30 seconds. Starting as a tender gay duet between Kimmel and Affleck, by the end, a We Are the World-style celebrity choir featuring Joan Jett, Meatloaf, Cameron Diaz and Brad Pitt have explained that Affleck and Kimmel's reltionship is “not just a man crush”, and Harrison Ford has blown the happy “couple” a camp kiss.

All this suddenly makes Hollywood look like a radically different place from the one we had hitherto imagined. Here we were, kind of feeling sorry for all those American celebrities who - what with their punitive diets, 10pm bedtimes and notoriously non-existent senses of humour - were basically living in a penitents' retreat, but with gold taps and better weather.

Post-Kimmel and Silverman, however, it's clear things are very, very different. Maybe it's the effect of the writers' strike - after all, those actors have had nothing else to do for the past five months - but it looks like they're all having the time of their lives up there in the Hills. They're all swearing, drinking beer and mucking about posting silly things on YouTube, like a group of hyperactive kids in Scarborough - except, in this case, they have a collective fortune of $477 million.

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