The idea of buying something you see in a TV show by pressing a button on your remote or smartphone has long been the stuff of futurist gabbing or science fiction. Now NBC Universal and American Express are the latest to try to turn the idea into reality.

The companies have formed a partnership that will let consumers purchase products "inspired by " NBC Universal programs directly from a mobile device while the programs are airing.

To do so, they'll use Zeebox, the social TV app in which NBC Universal and its parent Comcast Corp. took a stake earlier this year. The app, which works on certain tablets and smartphones, lets users converse in real time with friends who are watching the same show, or follow related Twitter and Facebook feeds. Under the new program, Zeebox will also give users information about how they can purchase show-related items such as couture and kitchenware.

NBC Universal's DailyCandy website will select the products that might appeal to viewers of shows such as Bravo's "Life After Top Chef," E!'s "Fashion Police" and Style's "Tia & Tamara."

American Express card members can receive $35 back when they use an eligible American Express Card, synced with their Facebook or Twitter accounts, to purchase one of the products.

"As viewer habits change and technology continues to evolve, and scale gets more elusive, context and impact mean everything," said Linda Yaccarino, president of NBC Universal ad sales, noting that more sponsors were seeking ways to play off the content their advertising supports instead of just running commercials that have little to do with the programs.

American Express sees the dawn of a new age of TV watching. "We're certainly not inventing advanced TV, but we think there's going to be a cultural shift," said Lou Paskalis, VP-global media content development and mobile marketing at American Express. The company envisions the TV becoming a sort of two-way digital hearth, he said, "where a lot of information is exchanged, as opposed to simply consumed, whether it be entertainment information or commerce-enabling information."

For decades, it seems, networks have dreamed of selling, say, the sweater Rachel Green wore on the latest episode of "Friends." To update this for contemporary TV, perhaps they'd like to sell one of the waitress outfits on "Two Broke Girls" or the cardigan worn by Claire Dunphy on "Modern Family. NBC Universal's program with American Express is still only a tentative step toward that notion. SeenOn.com has been working in that direction for several years. The SeeLoveBuy app is a more recent arrival in the nascent space.

American Express isn't expecting millions of dollars in transactions to take place this time around, Mr. Paskalis said, but rather wants consumers to see the company enabling new ways of purchasing goods and interacting with programming.

"Consumers are impulsive and we realize how impulse sales in part of our business are driven by TV," he said. While people who might try so-called "television commerce" today "are really savvy and sophisticated," Mr. Paskaslis said, "in the future, it's going to tip to an even broader audience, and they're going to be able to transact on any screen. We're at the very start of the journey."

Devising these ideas for advertisers is critical for Ms. Yaccarino and for NBC Universal, as both have something to prove. The company is eager to demonstrate the new ideas it can bring to market using the broad portfolio of media assets assembled when Comcast took majority control of the company in January 2011. Ms. Yaccarino was named to oversee all of NBC Universal's ad sales in September, placing her in charge of what may well be the broadest group of outlets -- and ad inventory -- in the media business.

The deal could also be a boost for the emerging practice of so-called "social TV," in which TV networks and advertisers are trying to find ways to reach viewers who are using "second screens" to talk, tweet and post about their favorite programs while they are on the air.

NBC Universal is working on more ad packages that involve social TV and Zeebox, Ms. Yaccarino said. "We are in the process of developing several different opportunities, from sports extensions at our company all the way to entertainment, whether it's broadcast or cable."