At the age of 70, French pianist Jacques Loussier has turned his suave classical jazz hand to Chopin's 'Nocturnes', writes Stuart Nicholson.

Jazz and classical music represent two self-contained musical cultures that for the most part have avoided each other's orbit. Yet the French pianist Jacques Loussier embraces both these worlds. For 45 years he has built an international following with a suave mix of the sacred and the profane, playing jazzed-up versions of classic J.S. Bach compositions, from the Toccata and Fugue in D Minor to Air on a G String. Sales of his albums exceed seven million and on October 26th he celebrated his 70th birthday. There was a BBC TV documentary on his life and a concert at London's Royal Festival Hall, while this month sees the release of his latest album, Impressions on Chopin's Nocturnes.

Loussier looks as if he is in his early 50s. Tall, lithe and with a goatee replacing the super cool, pencil-thin beard of his early years, he is as busy as ever. He tours extensively and is already planning his next album, which he will record in 2005. Initially, when his mix of jazz improvisation and Bach themes was released in 1959 it was not without controversy. "It shocked many a purist," he says with a characteristic Gallic laugh. "At the time it didn't even bother me, I so deeply felt the themes 'swung' naturally. I could change the chords somewhat, I could alter the rhythms slightly and make them glide towards jazz, and it worked. It was cool, it was open, it had everything!"

The album was an instant success, much to his surprise: "I really thought I was going to grab 25 copies and give them away to my friends and that was it. I never thought I would be a success," he says with a smile. The album caught the public's imagination and its commercial success shaped his career for the next 40 years. Yet whatever the purists might think, the prospect of combining jazz and classical music has long held an allure for musicians and public. George Gershwin's Rhapsody In Blue, which received its première at the hands of the Paul Whiteman Orchestra at the Aeolian Hall in London on February 12th, 1924, or Robert Graettinger's City of Glass, a stunningly modernistic composition for the Stan Kenton Orchestra that received its début in Chicago in 1948, are two early examples of large-scale musical adventures combining jazz and classical that continue to impress even today.

Yet it is a mistake to think of all this as jazz aspiring to claim something of the artistic legitimacy associated with classical music. In the early 1920s, Les Six - the French composers Georges Auric, Louis Durey, Arthur Honegger, Darius Milhaud, Francis Poulenc and Germaine Tailleferre - shared a fascination with jazz. This provided a source of inspiration in their own works where, they claimed, they "fused art and modern life", so challenging Impressionism in the hope of invoking a new French art music based on popular sources.

This two-way traffic moved up a gear in the late 1930s and early 1940s when there was a brief craze for jazzing the classics - Benny Goodman recorded Bach Goes To Town, a jazz fugue written by the British composer Alec Templeton; Tommy Dorsey recorded Rimsky-Korsakov's Song of India; the John Kirby Sextet recorded any number of tightly swinging classical themes; and Artie Shaw went the whole hog and commissioned a Concerto for Clarinet. There was even a movement in the 1950s called Third Stream that attempted to fuse jazz and classical elements that had some conspicuous successes, such as George Russell's All About Rosie, but it collapsed under the weight of its own pretensions.

Probably the most successful, and enduring, blend of classical and jazz elements was achieved at the hands of the Modern Jazz Quartet (MJQ), whose pianist and musical director John Lewis borrowed devices from Bach to Italian Commedia dell' Arte and successfully incorporated them into jazz expressionism. The MJQ's work had a profound effect on Loussier when he was studying piano at the Conservatoire Nationale de Musique in Paris in the 1950s, encouraging him to combine Bach with jazz as a diversion during lunchtimes on the piano in the conservatory's cafeteria for the amusement of his student friends. Yet on graduation, Loussier was unsure of what path to choose: "Classical music? Too classical! Pop music? Not classical enough! Jazz? Come off it, I'm not from New Orleans!" he recalls.

In 1959, Decca wanted to record him, but it too was unsure how to market him. But once Loussier played his jazzed-up Bach, his destiny was decided. A succession of Play Bach recordings followed that made his name.

Subsequently, he has spent most of his career playing the music of J.S. Bach, but in the 1990s decided to see how other icons of the classical canon responded to a jazz facelift. "Today the technique is well oiled," he says, "but it took me more than 30 years to master it with Bach, and a few more years to make up my mind to try it with other composers. If jazz was already present in Bach's music, what about Mozart, or Beethoven's? How could the rhythmic improvisations be integrated into these naturally less 'swinging' works without distorting them?"

With his latest album, Impressions on Chopin's Nocturnes, he has decided to make the first solo album of his career. "For the music of Chopin, which is so focused on the piano itself, it did not seem appropriate to use bass and drums," he says. "He . . . always wrote principally for the piano, and he was so devoted to the idea of it as a solo instrument it did not seem suitable to change this focus."

It's no coincidence that some of jazz's great pianists were also accomplished classical players - Willie "The Lion" Smith, James P. Johnson, Oscar Peterson and Bill Evans, for example, all applied their considerable musical technique to jazz improvisation.

But for Loussier, using classical themes as a vehicle for jazz improvisation rather than going down the usual route of improvising on jazz standards has provided him with a musical identity. It's amazing how many people have heard his jazzy version of Bach's Air on a G String. Yet the closer you listen to him improvising on Bach themes, the smaller the gap between classical music and jazz appears, revealing just how close the link is between the two forms.

* Impressions on Chopin's Nocturnes by Jacques Loussier (Telarc) is available now.