There’s a new perk for American Express Co. cardholders—the ability to access exclusive deals on Twitter.

American Express is rolling out an offering that enables its cardholders to sync their cards to their Twitter accounts. Then, when a shopper tweets using a special offer hashtag, the applicable discount is automatically loaded onto his account and applied “within days” when he uses his card at the participating merchant. On Twitter, a hashtag is a hyperlinked keyword. Any word that starts with a pound sign (#) is a hashtag, which becomes a clickable link to all other mentions of that word. For example, a tweet that says, “Welcome to #twitter!” makes Twitter a clickable link that brings up other tweets about that term.

Consumers can find the special offer discount hashtags by clicking on the Favorites tab on the American Express Twitter page. There the shopper can see a range of tweets from participating merchants. For instance, 1-800-Flowers.com Inc. tweeted “Tweet #Amex1800flowers, get $10 back 1x on next $50+ online purch w/synced Amex Card! (Exp 4/30) See terms aexp.co/YMZ.”  1-800-Flowers is No. 45 in the Internet Retailer Top 500 Guide. Among the other retailers offering discounts are Best Buy (No. 11), Sports Authority (No. 223) and Zappos, which is owned by Amazon.com Inc. (No. 1).

“American Express is turning Twitter content into commerce by connecting card members to merchants and delivering real-world value to both,” says Ed Gilligan, vice chairman, American Express. “With the continued convergence of online and offline commerce, our closed loop continues to enable us to bring seamless, relevant ways to connect our card members and merchants on the most powerful social and digital platforms.”

Twitter says the offering should be beneficial to both consumers and retailers. “Every day millions of people use Twitter to get special offers from the brands and retailers they care about,” says Adam Bain, Twitter’s president of global revenue. “Now American Express is making it even easier for people to act on those offers.”

The move is the latest collaboration between Twitter and American Express. Last month Twitter announced that initially only U.S.-based American Express cardholders and merchants who accept American Express cards can buy Promoted Product ads on Twitter.