Sorry, ladies.

That glittery, champagne-colored J.Crew cardigan first lady Michelle Obama wore during a visit at No. 10 Downing Street in London quickly sold out after photos of it flashed around the world yesterday.

Whether it was a meeting with the British prime minister and his wife or a reception with the queen at Buckingham Palace, all eyes were on the woman whom one British paper dubbed "Mighty Michelle" as she accompanied her husband to this week's G-20 summit of world leaders.

Not since Jacqueline Kennedy dazzled Europeans during her 1961 trip overseas has a presidential spouse's fashion choices so enraptured the media on both sides of the Atlantic -- "a razzle-dazzling performance," according to the London Evening Standard, while SELF Magazine's Senior Fashion Market Editor Lindsay Taylor praised Mrs. Obama's "effortlessly chic, classic style."

Shoppers, too, flocked to J.Crew and other stores yesterday to copy what fashion experts call the first lady's uniquely American taste in clothing.

That would be American as in: youthful, athletic, "glamazonian," said Mandi Norwood, author of the forthcoming book "Michelle Style: Celebrating the First Lady of Fashion."

Compared with the somber tones sported by Mrs. Obama's husband, President Barack Obama, and Prime Minister Gordon Brown and his wife Sarah -- who, Ms. Norwood observed, "looked like a dowdy nanny next to the glittering Mrs. O"-- the first lady "totally nailed modern power dressing on this trip."

In the old days, power dressing meant sharp, angular lines and aggressive colors, but these days, "by not wearing a skirt suit, [Mrs. Obama] is really setting herself apart from previous first ladies," said Tori Mistick, a fashion designer based in Shadyside. "The cardigans give her an approachable look, they are softer and less structured than a blazer -- two qualities that reflect her approach to life."

"I do think overall [Mrs. Obama's] style is very American," added Jenna Lyons, creative director at J.Crew in New York City, who was thrilled and surprised to see her company's creations on the first lady yesterday. Indeed, at the J.Crew store in Shadyside, customers were asking where they could buy the outfit -- a $298 beaded crystal cardigan and $158 pencil skirt in mint cotton jacquard, along with an $18 "perfect-fit" tee. (The cardigan may be gone, but the skirt is available online and the T-shirt is in stores.)

At least one young woman walking past the J.Crew store in Shadyside seemed unimpressed, however.

"It's very democratic clothing, in that it's inexpensive, but she's first lady, maybe she should try something a little pricier, like Dolce & Gabbana or Versace, if she wants to be a style icon," said Estefania Capparelli, 21, a student at Community College of Allegheny County.

But being a style icon these days may mean something more eclectic than wearing a high-end designer -- it's about "shopping your closet" for different pieces, Ms. Lyons said, or "repurposing" a belt with different outfits, as Mrs. Obama has.

"It's about separates, about having your personality," Ms. Lyons added, noting that one lasting contribution to fashion came from designers of classic American sportswear in the mid-20th century. By eschewing a head-to-toe, matchy-matchy uniform, Mrs. Obama is "saying so many things -- that she's feminine, a woman, a mom and still attractive, and I think that's really refreshing."

By contrast, the other fashion icon at the G-20 summit this week, France's first lady Carla Bruni-Sarkozy, is going more in the direction of the square-ish suits favored by first ladies in recent decades. Mrs. Bruni-Sarkozy "used to be very feminine but now is making herself look like a rectangle," Ms. Lyons said.

Whether it was a custom ivory tweed Thakoon coat and Jimmy Choos en route to Air Force One, or a black duster and chartreuse sheath from designer Jason Wu stepping off the plane, Mrs. Obama elicited mostly positive reviews even as some wondered -- and others worried -- that she would go sleeveless when meeting the Queen.

"That would not be a good idea," said Elena Curti, deputy editor of The Tablet, a British Catholic weekly. "She would look rather underdressed." Last year, Ms. Curti noted, Mrs. Bruni-Sarkozy wore muted colors and gloves when meeting the monarch, "and got it absolutely right."

At the Buckingham Palace reception for G-20 leaders, Mrs. Obama didn't go sleeveless, choosing instead to wear a black Jason Wu coat, Isabel Toledo dress and black Alaia cardigan -- but neither she nor the Queen wore gloves. And it should be noted that Mrs. Kennedy and Queen Elizabeth both wore sleeveless gowns at a dinner in 1961.

Actually, Ms. Curti noted, the British press believes Mrs. Obama's biggest faux pas during a previous White House visit by British Prime Minister Gordon Brown and his wife Sarah involved not clothes, but gifts. "For the Obama girls, Sarah Brown carefully chose children's books by leading British authors and dresses from Top Shop," Ms. Curti said. "Michelle just picked up a couple of toy helicopters from the White House shop. It hasn't been forgotten."

Reportedly, the Obamas presented the Queen yesterday with an iPod loaded with video and photos of her 2007 trip to the United States, as well as other songs and accessories -- and a rare songbook signed by famed 20th-century composer Richard Rodgers.

Sounds like a great gift -- even if the Queen already has an iPod.