They run no fewer than 5 fashion businesses -- from the impossibly high end The Row to the Olsenboye line for J.C. Penney -- but somehow, Mary Kate and Ashley Olsen have managed to elude the adult celeb fragrance category -- till now.

After two years in development, hitting Sephora shelves exclusively at the end of January (following a "holiday preview" run from December 13-25) will be the world's most famous twins' first foray into fragrance -- a dual set of scents called "Nirvana."

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According to WWD, the "White" counterpart is "a musky floral built around peony, Puget and musk," while "Black" is sensual and woodsy "featuring sandalwood, lavender and vanilla." They can be "layered" or worn separately as desired.

How did the scents -- and the partnership with Sephora come about? As WWD explains:

"Roughly two years ago, Sephora's Kendo division -- the development arm that handles strategic partnerships -- approached Mary-Kate and Ashley after a fashion market research survey commissioned by the beauty retailer continually referenced the Olsens' Elizabeth and James brand. "We always knew we wanted to have a fragrance for this brand, because it's very lifestyle," said Ashley. "There are many components to the brand. We felt that between the brand Elizabeth and James and Sephora that we were really speaking together directly to our customer. We felt that was a really good place to start exploring the world of fragrance and beauty."

Elizabeth and James Nirvana eaux de parfum will each be available in three sizes -- 50 ml. for $75, 30 ml. for $55 and a $22 rollerball. Look for them beginning December 13 at Sephora stores. And, to read WWD's exclusive interview with the elusive pair, click here.

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