The first lady wears a custom Thom Browne coat and dress, "both made of silk jacquard based on a necktie fabric," reports Eric Wilson of the New York Times.
The full scoop from a White House official via the press pool:
"The First Lady is wearing a navy Thom Browne coat and dress. The fabric was developed based on the style of a men's silk tie. The belt she is wearing is from J.Crew, the cardigan is designed by Reed Krakoff and her necklace is designed by Cathy Waterman. She is also wearing J.Crew shoes. At the end of the inauguration, the outfit and accompanying accessories will go to the National Archives.
Malia Obama is wearing a J.Crew ensemble. Sasha Obama is wearing a Kate Spade coat and dress."
Additional details to note: Marian Robinson wears hand carved, hand painted Lucite allegory flower earrings in black from Alexis Bittar.
This is not the first time that Mrs. O has worn Thom Browne. The first lady wore his lace overlay dress for the Democratic National Convention in September 2012, seen here. The designer is the recipient of the 2012 National Design Award in Fashion Design, celebrated with a White House luncheon ceremony hosted by the first lady.