Buttmunches beware. Beavis and Butt-Head, MTV's top couch retards, will be "dumbing down" Britain over the next month. The pubescent postmodernists are preparing the ground for their big-screen debut, Beavis and Butt-Head do America (released here on 23 May), by going on the road.

A three-week bus tour sees the animated onanists servicing cities from Glasgow to Portsmouth with a kind of scatalogical Swapshop which includes infantile competitions (such as the much-sought-after "best bogie-flicker") and live music. After beating off the crowds, the pizza-faced celebrities will be scouring for an honorary dumb-ass "European cousin". So if you're a prize buttwipe, you might just find yourself animated into the boys' next TV series.

Beavis and Butt-Head will be starting their rude roadshow at London Music Week film season, a festival of talks and screenings exploring the relationship between the international music and film industries. As well as talks by the likes of Roger Daltrey, the event will preview movies by such musical icons as Diana Ross - who will be here in person to explain how she made the journey from The Supremes to "a promising medical student struck down by schizophrenia" in the film Out of Darkness.

If the idea of a bi-polar Ross sounds outlandish, then try Chris "The Road to Hell" Rea's concept-album of a movie, La Passione, for size. A "musical fantasy", the film's pop operettas are loosely woven around a small boy's fantasies about sports cars. The title song, "Shirley, Do You Own a Ferrari?", is sung by Shirley Bassey.

"People warned me that I'd get a certain amount of sarcasm about the cars," says Rea (who spent hours reconstructing the 156 Sharknose Ferrari to star in the movie), "but it's not a playboy thing. It's more religious, the whole mystique of Italy and red cars."

Although the film is not autobiographical, Rea admits that "like many boys between the age of 8 and 12 [he] had a mystical experience". This seems to have involved motors in some way but, keen to stress that such childhood epiphanies don't necessarily have to involve cars, he reveals that he's "written a sister script" to La Passione "which has the same scenario for a girl on a horse." Asked about the visual style of his screen debut, Rea replies "Somebody mentioned the word Fellini". Perhaps Beavis and Butt-Head should call off the search for their European cousin right now.

Beavis and Butt-Head are at a cinema near you this week. London Music week events at Screen on the Green, London N1 (0171-226 3520) 28 April to 1 May Liese Spencer