Facebook Messenger and WhatsApp could be merging in the future, allowing users to chat across apps, no matter which one they themselves are using.
Facebook - which has owned WhatsApp since 2014 - is said to be testing the new feature, according to WABetaInfo, which regularly trawls the code of apps to uncover clues to upcoming features with some degree of accuracy.
The website said it found evidence of the merge within the code of Facebook Messenger, though it's unclear when the feature could be rolled out.
WABetaInfo notes that the merging of the two apps is not "available yet," and might not even come to fruition, as the feature is "very complicated" and "requires so much time."
"We’ve no idea if the plan to merge those services will continue or if it will be abandoned and discarded," it adds.
What could the merge mean for users?
Should the merge go ahead, one person could reach another contact on WhatsApp through the Facebook Messenger app, and vice versa.
That raises some interesting security questions.
WhatsApp is famous for its end-to-end encryption, which keeps the content of a user's messages secure - users also need only a phone number to sign up.
Facebook requires a person’s “real” identity to register, and its Messenger app is not currently encrypted in the same way WhatsApp is.
Facebook has previously said, "We’re working on making more of our messaging products end-to-end encrypted."
The news of the potential merger comes just a year after Facebook boss Mark Zuckerberg said he wanted to see greater integration between Facebook, Instagram and WhatsApp.
"As you would expect, there is a lot of discussion and debate as we begin the long process of figuring out all the details of how this will work," said Facebook.