Just two days after Jawbone announced that it will finally ship its heart rate tracking wearable, UP3, even though the tracker will not be waterproof as initially advertised, an anonymous source told the Wall Street Journal that American Express is working with Jawbone to add payment features to a future wearable.

According to the report, American Express cardholders who buy this future Jawbone device will be able to make purchases at the brick and mortar locations of some vendors that have near-field communication, or NFC, enabled at their registers. 

It's unclear when Jawbone's future device will launch or whether it will accept payments from other credit cards or banks.

A few other wearable device companies have announced payment features.

The most high profile announcement came from Apple, which added Apple Pay, the company's payments offering, to its Apple Watch, which is set to launch next week. With Apple Pay, users can make electronic payments without Apple seeing what they bought, who they bought it from, or how much they paid. And the cashier doesn’t see the user’s name, credit card number or security number.

Major credit cards, including American Express, Visa, and MasterCard are participating in Apple Pay as well as a number of banks, like Bank of America, Capital One, and Chase.

And while Microsoft's activity device, the Microsoft Band, doesn't offer general payments, users can sync the band with their Starbucks account and pay for coffee or food at Starbucks from their device.