Art for rock's sake: Among the musical elite, swapping a guitar for a paintbrush comes naturally

What is it with modern musicians and painting? What spurious orthodoxy now decrees that no rock star of note reaches his/her 50th birthday without having an exhibition of scratchy-dauby artworks launched in a major gallery? Did Schubert or Liszt or Beethoven pause in their labours at the keyboard to knock off charming watercolours of the scene from their music-room window? No. Today, you can't throw a paintbrush across Cork Street without hitting another ageing rocker mounting canvases onto a whitewashed wall.

A dozen of Bob Dylan's pastel works are going on display at the National Portrait Gallery, from late August to early January. This is not a new event for him. His 1989-92 drawings were exhibited at the Halcyon Gallery in 2008, and he's been exhibited at the Gagosian in New York, which brought Damien Hirst to the attention of the Manhattan art world. Dylan has been painting for years: the cover of his 1970 album Self-Portrait was, indeed, a self-portrait, indifferently rendered.

Dylan paints, reportedly, to alleviate the boredom of touring. So did Jimi Hendrix, whose pen-and-watercolour creations were made on the road with his band.

Other rockers started their creative lives at art school. John Lennon attended Liverpool Art Institute and drew pencil drawings all his life. Syd Barrett started painting at school and returned to his teen passion after leaving Pink Floyd. Ronnie Wood, later to become the nation's most celebrated rock artist, went to London's Ealing Art College before joining the Small Faces. Bill Clinton is among those who have bought his art.

Joni Mitchell's art has featured on several of her albums, from Clouds and Ladies of the Canyon; her online gallery currently offers 289 works. She has said in interviews that she's "a painter first and a musician second" and that she got "derailed" from her true career by the inconvenience of having a stunning voice and guitar technique.

Once you look around, it's remarkable how seriously rockers take their art hobby. Thom Yorke from Radiohead has collaborated for more than 10 years with an artist called Stanley Donwood under the collective name of The White Chocolate Farm, producing lots of Radiohead-album artwork.

Paul Simenon of The Clash is a strikingly accomplished painter and has had eight exhibitions around the UK; the most recent features his impressions from a trip to Spain. Marilyn Manson used to sell watercolour sketches to drug dealers; he now exhibits his Gothic work on both sides of the Atlantic, especially his jagged triptych of Jesus Christ. Paul McCartney's monumental oils have been exhibited many times; the Queen came to check them out at Liverpool's Walker Art Gallery. The Beatle's paintings have been seriously compared to those of Willem de Kooning. Jim Morrison of The Doors and John Squire of The Stone Roses were both inspired to paint by the manic energy and abstract impressionism of Jackson Pollock.

Why might they all be attracted by pen or brushstrokes on paper or canvas? Donna Summer has the answer. "The difference between painting and performing," she says, "is that, at the end of a concert there is nothing left but a sense of elation that diminishes with time. With painting, whatever I put down on the canvas is there when I wake up next day, and forever."