Everyday women with an eye for fashion might have an unlikely hero in Facebook Live (FB - Get Report) , the social media platform high-end brands are using to broadcast New York Fashion Week in real-time.

Kate Spade (KATE) will unveil its spring collection from New York Fashion Week on Facebook Live at 11:30 a.m. EST, while Calvin Klein (PVH - Get Report)  began live streaming its fall 2017 collection at 10 a.m. EST.

"I think it's a great fit," said David Hewitt, VP of consumer experiences at marketing and technology consultancy SapientRazorfish. "Facebook Live brings a sense of authenticity to posts."

The platform works especially well for fashion shows, since the events can create a sense of intimacy with behind-the-scenes footage and celebrity appearances. 

Actress and singer Victoria Justice will host Kate Spade's live stream today.

Celebrity hosts attract more viewers than traditional videos do, expanding companies' reach, while behind-the-scenes campaigns give consumers brand affinity, Hewitt said.

The live format also allows users to comment in real time, granting retailers an immediate sense of which outfits are hits and misses. 

Facebook has essentially transferred the spirit of a live audience onto a mobile platform with the comments function, Hewitt said.

"When you have most folks sitting behind mobile screens and TV, rarely do you get to take that energy and archive it with that video" Hewitt said. "I think that's pretty cool."

Even after the live stream ends, companies can leverage the data they've collected about viewers to create targeted advertisements, said Kevin Shively, director of marketing communications at social analytics company Simply Measured.

Some public relations agencies that work with retailers might be hesitant to cede control of their brand's messaging, as required by live broadcasts.

But fashion shows' relatively controlled format mediates some of these risks.

"I think [Facebook Live] is a viable tool in the toolbox, but it needs to be used in the right way," Hewitt said. "I think a fashion show is the perfect venue."

New York Fashion Week runs from Feb. 9 to Feb. 16.

Kate Spade and Calvin Klein parent company PVH Corp. didn't immediately return requests for comment. 

Jim Cramer and the AAP team hold a position in Facebook for their Action Alerts PLUS charitable trust portfolio.