She may be best known for the Manolos worn by her alter ego Carrie Bradshaw in Sex and the City, but hot on the heels of her eponymous shoe line, Sarah Jessica Parker proves she is a dab hand at jewellery design too.

The New York-based actress has collaborated with fine jewellery artist Cindy Chao to create a one-of-a-kind Black Label Masterpiece Ballerina Butterfly brooch, which will be auctioned at Sotheby's Hong Kong Magnificent Jewels and Jadeite Sale this October, with net proceeds benefitting the New York City Ballet.

Parker and Chao first met at the Masterpiece Exhibition in Beijing three years ago and decided to work together in 2012 when the actress was a guest of honour at the opening of Chao's boutique in the same city.

The brooch is the result of two years of hard work, during which the pair met several times to discuss sketches, wax models and gemstones. As with all her Black Label Masterpiece creations, Chao started the creative process by constructing a wax model of the brooch. The finished piece is the perfect amalgamation of Chao's craftsmanship and Parker's astute eye for style and design.

With a gold and titanium body, the 2014 Black Label Masterpiece Ballerina Butterfly brooch was inspired by the graceful beauty and elegance of ballet, a discipline close to Sarah Jessica Parker's heart, who attended the School of American Ballet in New York. The brooch features a cushion-cut fancy brown diamond weighing 26.27 carats as well as three rough brown diamond slices totalling 47.71 carats and three rare conch pearls. These are surrounded by 98.09 carats of diamonds and fancy coloured diamonds.

This year marks the 10th anniversary of the Cindy Chao brand, which is renowned for its unique, sculptural jewellery. The Black Label Masterpiece Butterfly was first introduced in 2008 and, since then, Chao has designed a different one every year to symbolise her metamorphosis as an artist.

Chao says: "Sarah Jessica and I are two very different creative minds sharing the same artistic vision and passion. She truly appreciates the essence and soul of my creations, and I admire her innovative yet classic view on fashion and style. My annual Butterflies carry special meaning for me. Collaborating with Sarah Jessica for a cause we both deeply care for and believe in makes this Ballerina Butterfly all the more special in my heart."

Parker readily returns the compliment: "I have had the great pleasure of knowing Cindy and her work for several years, and it has been an incredibly special experience to collaborate with her. Cindy's jewellery designs are true works of art; they capture the eye and imagination in a memorable way. I am so pleased to partner with her on this project, which benefits the wonderful work of the New York City Ballet, an organisation that is close to my heart."

The Ballerina Butterfly brooch is being shown this week in Paris as part of Haute Couture week in the capital before touring throughout Asia and then on to New York, where Chao and Parker will co-chair the New York City Ballet's Fall Gala in September. It will return to Hong Kong in time for the Sotheby's auction on 7 October 2014, where it is estimated to sell for between $750,000 and $950,000.