Twitter has begun testing a 'buy' button that merchants can embed in tweets so that shoppers are able to make purchases from within the social network.
Twitter says that a "small percentage" of its US users will now be able to see the buy button when they view the social network using the iOS and Android apps.
Users who tap on the button will be shown additional product details and prompted to enter their shipping and payment details. After making their first purchase, tweeters will have their details encrypted and stored so that they do not need to re-enter them for future transactions.
As widely trailed, Twitter is working with Stripe on the system and has also enlisted social shopping firm Fancy and digital selling platforms Gumroad and Musictoday.
Among the small number of brands, non-profits and artists to test the service are Burberry, The Nature Conservancy and Eminem. More sellers and more users will be added over time.
Tarun Jain, group product manager, Twitter, says: "This is an early step in our building functionality into Twitter to make shopping from mobile devices convenient and easy, hopefully even fun."
Twitter's move into commerce has been widely touted - in July it acquired CardSpring, a firm which provides an API designed to make it easy for developers to link digital applications to payment cards. And it is not the only social network to test a buy button - Facebook began its own trial over the summer, enabling users to purchase products advertised on the site.