Photography by Anön.

It may come as a surprise that classically trained cellist Zoë Keating has 1,029,679 (and counting) subscribers on Twitter and is listed among the top 120 suggested Twitterers to follow—right up there with Martha Stewart, 50 Cent and Britney Spears. With a genre-bending sound she creates by playing a French cello that’s layered and looped using a foot-pedal-controlled MacBook, it’s no wonder this former software engineer turned one-woman orchestra attracts a diverse audience as intrigued by the arts as they are by technology.

But ask the self-proclaimed “amateur nerd” to describe her unique sound and she won’t. “I can play for a classical audience, or a steampunk goth cabaret crowd, or for the emo crowd,” says Keating, whose innovative sound partly grew out of living with other experimental musicians in a Natoma Street warehouse. She lived there for years before her recent move to the North Bay. “I try to stay away from defining a subculture because my music doesn’t really fit into any of them.”

When she’s not hosting spontaneous “cello tweet-ups” outside City Hall, working from her countryside studio on her second self-produced album, aptly named Into the Forest, or collaborating with her graphic-designer husband on a multimedia performance project (funded by a recent $15,000 grant she won from the arts nonprofit Creative Capital), you might catch Keating relaxing with friends on a “musical vacation.” “We’ll bring all of our instruments and play music for no purpose,” says Keating of an upcoming trip to Scotland. “Not to rehearse. No agenda. Just for rocking out.”

Stylist: Rachel Lena Esterline. Styling assistance: Sonie Hack. Hair + Makeup: Pircilla Pae for Shu Uemura. Azzedine Alaïa dress ($3,585), Lanvin pearl-and-lace necklace ($995) and Simone Coste gold ring ($2,780) at Barneys New York, 415-268-3500. Vintage sheer tulle skirt, stylist’s own. Cream lace bloomers, shredded tights and vintage Victorian boots, model’s own.

Check out the other 2009 Hot 20.