One of the strongest micro trends for Fall 2011 is the Peter Pan collar. This slight school girl look was seen on many a runway, including Giambattista Valli, DKNY, and Marc Jacobs. Marc used it most prominently in his collection for Louis Vuitton where leather white collars (often detachable) were paired with 1930s inspired dresses.
Extremely popular in that particular decade, one notable movie moment the collar can be traced to is Claudette Colbert in 1934's It Happened One Night. You can see how many of the details from her famous costume were carried forward--the laser-cut ruffled edge in the collar, oversized buttons down the front, tone on tone patterns in the rich fabric, and slim fit skirts flaring just below the knee. The 30s were also referenced in his collection's exaggerated pantyhose and classic shoes.
Though I admire the artistry and talent these reinterpretations take, they're actually a bit too much for my own personal style. In my opinion, Columbia costume designer Robert Kalloch got it just right on Claudette, including that great skinny belt to accentuate her waist. Always inspirational, I continue to be amazed at how everything in fashion can find its origins in film.