When Karl Lagerfeld introduced his ridiculously oversize hula-hoop beach bag at a Chanel runway show last month, he inadvertently struck a pop-cultural chord.

Among the most talked-about accessories to emerge from this season’s shows, the beach bag seemed to have tapped into a newfound affection for the hula hoop, as a fashion statement and an exercise device.

Anderson Cooper, on his recently canceled talk show, Anderson Live, presented a mock version of the bag — a quilted white case with handles made of actual hula hoops — to his co-host, Alexa Chung. A video of Lagerfeld explaining the bag (“It’s for the beach. You can put it into the sand and hang things on it.”) has been popping up on fashion sites like Fashionista and Styleite. And last week, Chanel announced that it would be selling smaller versions in stores.

Hula hoops have received other celebrity endorsements. Christie Brinkley was photographed hula-hooping in Times Square on Oct. 5 for World Smile Day, an event that promotes acts of kindness. Jimmy Fallon challenged Michelle Obama to a hula-hooping contest on Late Night With JimmyFallon in February, after she was photographed hooping on the White House lawn at her Healthy Kids Fair. And Marisa Tomei professed her love of hula-hooping on the Ellen DeGeneres Show in 2010, saying it “shimmied everything into place” for her role as a stripper in the film The Wrestler.

Veteran hula-hoopers have long stood by its aerobic virtues.

“A lot of people are interested in hooping for its health benefits, which might get them hooked, but it’s also such a fun way to do cardio,” said Bex Burton, a hula hoop instructor who founded Sense of Motion, a Brooklyn-based company that teaches hula-hooping, Pilates and yoga.

As with any exercise trend, accessories have proliferated.

“We just got in a beautiful prototype of a goatskin-covered hula hoop — it’s dark black leather with a nice grip,” said Gabriella Redding, founder of Hoopnotica, a fitness company based near Venice Beach in Los Angeles. In addition to selling hoops, fitness videos and other accessories, Hoopnotica certifies 300 instructors a year to teach what it calls hoop dance.

Sales at the 7-year-old company have grown an average of 30 percent each year and passed the $1 million mark last year, Redding said.Die-hard hoopers are also taking their passion outdoors, to concerts and giant group hoop sessions called “hoop jams” set to music. Devotees can be spotted in the subway with oversize hoop bags.

“Everyone is in their own hoop world at hoop jams,” said Jenni Schwartz, 32, a graphic and Web designer in Manhattan. “But it’s friendly at the same time, so I know I can always ask someone to teach me a new skill.”

The trend is bicoastal. In Los Angeles, workplaces are embracing hooping as a healthy alternative to smoke breaks or trips to the vending machine.

Dina Strada, the manager of employee events at DreamWorks Animation, encourages the staff to take hoop breaks twice a day for 15 minutes. About 10 to 15 people partake, she said.

“Even on days where we’re so crazed with work, we force each other to take a quick break,” Strada said. “On really busy days, I can hoop and respond to emails at the same time.”