"Harry Winston, tell me all about it!" sang Marilyn Monroe breathlessly in Diamonds are a Girl's Best Friend. Now Swatch is paying up to $1bn (£619m) for the glamorous jeweller and watchmaker in a hope of buying a piece of Hollywood legend.

The world's biggest watchmaker is paying $750m for Harry Winston, which employs 535 people, plus up to $250m of net debt. It is not buying Harry Winston's mining activities.

The chair of Swatch, Nayla Hayek, said: "Harry Winston does brilliantly complement the prestige segment of the group. We are proud and happy to welcome Harry Winston to the Swatch Group family," adding, perhaps inevitably: "Diamonds are still a girl's best friend."

It is Swatch's first big takeover in years and comes as watchmakers race to buy up know-how and production facilities around the world. Swatch already owns luxury brand Omega – the watch of choice for James Bond, as portrayed by Daniel Craig – as well as Breguet, Blancpain and Jaquet Droz. It has bought several component makers over the past years, but it has been more than a decade since it bought a major watch brand.

Robert Gannicott, the chairman and chief executive of Harry Winston, said: "The Harry Winston brand now has a new home that can provide the skills and support that it deserves to realize its true potential."

Last week, Swatch beat expectations for global annual sales despite a slowdown in demand for its luxury watches in China.