ABC News' Deborah Roberts reports:
Michelle Obama is a fashion icon for the modern U.S. woman.
The first lady has been a showstopper with her formal wear, and has set a trend with her use of high-waisted belts.
Today was no different as Obama entered St. John's Episcopal Church for morning services wearing a belt and shoes from J. Crew, as well as earrings designed by Cathy Waterman. She also wore a navy Thom Browne coat and dress, with the fabric based on the style of a man's silk tie. The outfit and accompanying accessories will go to the National Archives at the end of the inaugural festivities.
"It's always a guessing game," fashion designer Thakoon Panichgul said of the first lady's fashion today on "Good Morning America. "It's always a surprise, and I think that's what makes it so exciting. You never know what she's going to wear, and that's why people tune in so much to what she's going to be wearing."
She has shopped at Target, and appeared at several events wearing J. Crew apparel, thereby elevating ready-to-wear fashion.
"I think her style has become more streamlined," Kate Betts, author of "Everyday Icon: Michelle Obama and the Power of Style," said. "We're seeing less of the big-statement jewelry, less of the belts. A very sleek silhouette."
Her new hairdo - trendy bangs to mark her 49 th birthday last week - have also drawn some rave reviews.
She rarely makes fashion missteps, but manages to be relatable to the average woman, even dropping to do push-ups during an appearance on the talk show, "Ellen."
"She has this accessible side of her that allows women to really go out and buy what she's wearing. But in the evening, she's the first lady, with all the pomp and circumstance," said Robin Givhan, a contributor to the Washington Post.
"What she wears, there's always a certain pragmatism to it," Givhan said. "It's never outrageous, never inappropriate."
Even her daughters, Malia, 14, and Sasha, 11, have shared hand-me-downs, although today they're sporting vibrant colors with Malia in a pink overcoat and Sasha in purple.
"It seems like she's making a statement that these are regular girls who are living exceptional lives," Givhan added.
And as for what the fashion-forward first lady will be wearing at the inauguration this afternoon, only time will tell.
"I don't have the answer," author Betts said, "but I do think she'll be wearing long."