NEW YORK — TLC is launching an online-only event for its long-running hit “What Not to Wear” that offers a new take on TV and social media synergy: During the show’s first-ever studio-audience taping, fans will be able to vote on a guest’s style makeover at home with just a few clicks of a mouse.

There are a number of shows in development that are embedding social TV platforms to do similar things, but this might well be the first that will use social media to allow viewers to participate and influence the actual direction of the show, says Social TV Summit conference CEO Andy Batkin, who developed the branding and media strategy for Yahoo!’s launch. Batkin has consulted on several upcoming interactive shows — almost all in the reality TV genre — and says the first of the bunch are likely to debut at this May’s upfronts.

On the morning of the March 14 “What Not to Wear” taping, a description of the episode’s “contributor” (the official term for a style-challenged makeover subject) will be posted on the show’s website (at TLC.com) and Facebook page (facebook.com/WhatNotToWear). Photos of style options in categories based on the show’s trademark elements (rules, shopping, hair and items the contributor should “keep or toss”) will be posted shortly thereafter, and put to online votes.

TLC’s social media team will present the poll results (and a few user-submitted questions) to the show’s hosts, Stacy London and Clinton Kelly, hairstylist Ted Gibson, makeup artist Carmindy, the contributor, guest makeover subjects from past episodes and some 150 audience members recruited from the show’s online fan base. London, Kelly and Gibson will be able to overrule winning votes in the trashing (“keep or toss”) section, but all other audience choices will stand as final.

Fans will see real-time data on how votes are polling on the site, but won’t hear their questions to the hosts answered — or see their makeover choices unveiled — until the show airs at the end of May.

While the event seems a natural opportunity to promote a long-running show to new viewers, extend advertisers’ reach and cultivate an Internet audience that’s exploded since the 2003 “Wear” premiere, TLC senior director of production Stephanie Eno and TLC’s VP of digital Pamela Russo say their main goal is to engage the show’s core audience.

“We know from internal research that fans of TLC shows and the talent in them want to find a way to participate,” Russo says. “We have a pretty robust and sticky Facebook page for almost all our shows and for TLC itself. The byproduct is growing our social footprint, Twitter followers and Facebook fanpages, but for us the core is to serve those people that want to participate in our programming. Social media and (websites) are the vehicles to get there.”

Social TV, the catch-all term for new technology and other forms of interactivity between TV, Web, mobile and tablet audiences, has developed rapidly over the past few years, but interactivity that drives a program’s content has gotten off the ground a bit more slowly. Rare examples include the 2006 Finnish musical comedy series “Accidental Lovers,” in which viewer text voting determined the protagonists’ romantic plotline.

Online voting for contest-show winners and viewer-generated content have also seen a boost in recent months, from “American Idol” (which launched Web voting a year ago) to real-time viewer polls and questions on various news programs — along with onscreen live streaming of Facebook and Twitter comments.

Eno says the exec producer of “What Not to Wear,” Jo Honig of producers BBC Worldwide Prods., sees the increased interactivity as wish fulfillment, giving the show’s audience something it always wanted — to have a voice in the show. Using a live audience was the initial idea, and the online component soon followed.

The event will allow the show to tap into an already fervent (and opinionated) online fan base. “Wear” has 900,000 fans on its official Facebook page.

“Everyone has an opinion about fashion, and our Facebook page lights up like mad in agreement or disagreement while we’re airing a show that’s been shot weeks beforehand,” Eno says. “We thought, ‘Wouldn’t it be fun to have people (at home) have a voice in the decisions while we’re doing it?’?”

For now, calling the effort an experiment, Eno hopes to apply the idea to other popular TLC reality shows, including “Say Yes to the Dress.”

In addition to on-air marketing, newsletters and TLC.com, the event will be promoted via the Twitter and Facebook accounts of TLC (@TLC), London (@StacyLondonSays), Kelly (@clinton_kelly), Gibson (@tedgibson) and Carmindy (@CarmindyBeauty) — who have a total 280,000 Twitter subscribers.

“The goal is to engage the audience in a way they haven’t been engaged in the show before,” Eno says. “This is a good first step.”