She’s hailed as a fashion icon for her boho chic style, and now Sienna Miller is giving fans a chance to wear the very clothes she herself has donned everywhere from London’s High Street to the red carpets of Hollywood.

The actress and activist has selected a variety of dresses, jackets, jeans, boots, handbags, heels and hats from her own closet to be auctioned off via eBay through November 17, where 100 percent of the proceeds will benefit International Medical Corps, which seeks to provide emergency relief and health care services to tens of millions of people in over 65 countries. 

And in a nod to today’s ailing economy, there are no minimum bids, so even the budget-conscious can own a piece of Miller’s closet.

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But ditching her designer duds is only one of the many contributions the British star has made toward the organization, as she openly admits how appalled she was at herself for how little she knew about the problems of the world outside her entertainment industry bubble.

“I first heard about International Medical Corps about three years ago. I remember being in California and stumbling across this horrific statistic that burnt into my consciousness: one woman in the Congo is raped every eight minutes. It terrified me,” Miller told FOX411’s Pop Tarts column at the International Medical Corps’ 2011 Annual Awards Celebration in Beverly Hills last week, where she was honored with the Global Activist Award. “It terrified me not only because it exposed this violent abhorrence, but also because it exposed how unaware I was about the world I lived in. I felt embarrassed and angry. I was in that strange and frustrating place that I think we've all encountered when we learn about a great injustice and find ourselves suddenly impotent. You don't know what you can do about it. You don't know how to do anything about it. You don't have a weapon to fight it. International Medical Corps is that weapon.”

According to a source close to the project, Miller, who has been a long-time spokesperson and Global Ambassador for the humanitarian relief organization, is one of the rare gems in Hollywood who does a lot of giving without the lights and camera.

“Sienna has visited field programs in the Democratic Republic of Congo, Haiti and most recently, Ethiopia to raise awareness of the ongoing famine,” said our insider. “She does a lot of work and does so without the need for it to be broadcast to the world or to inflate her own ego. It is actually something she genuinely cares about.”