Cindy Chao and Sarah Jessica Parker design brooch for NYC Ballet

A one-off item created by the fine jewelry designer and the actress will be auctioned by Sotheby's Hong Kong in October, with proceeds going to the New York City Ballet.

While Sarah Jessica Parker has already designed shoes (through her own line) and apparel (with Halston Heritage), this collaboration marks her first foray into jewelry. The actress decided to make the leap in 2012, when she teamed up with fine jewelry designer Cindy Chao to create a one-of-a-kind item to be sold for charity.

Unveiled today, the "Ballerina Butterfly Black Label Masterpiece I 2014" brooch will be auctioned by Sotheby's Hong Kong in October, with proceeds going to the New York City Ballet.

"Sarah Jessica and I are two very different creative minds sharing the same artistic vision and passion," Chao said of the tie-up in a release.

In turn, Parker expressed her admiration for Chao's designs and her enthusiasm for the initiative. "Cindy's jewelry 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 organization that is close to my heart."

With a body made of titanium and 18K gold and inlaid with brown diamonds, fancy-colored diamonds and conch pearls, the brooch is sure to attract plenty of bids when it goes under the hammer this fall.