Women's Wear Daily was the first to report who designed the frock Mrs. Obama wore during Sunday morning's event in the Blue Room at the White House.
The Huffington Post said the American designer is also the president and executive creative director of Coach Inc.
As for her hair, the first lady sported trendy bangs for the ceremony, during which President Obama was sworn in for a second term.
E! said it had not yet been revealed what the first lady would wear to Monday's inauguration ceremony and subsequent inaugural balls.