The new titles will appear in the title for both apps in Apple's App Store and Google Play Store.
"We want to be clearer about the products and services that are part of Facebook," a spokesperson was quoted as saying.
Employees for the apps were recently notified about the changes, "which come as antitrust regulators are examining Facebook's acquisitions of both apps", said the report.
The US federal Trade Commission (FTC) is now probing what prompted Facebook to acquire Instagram and WhatsApp.
According to The Wall Street Journal, the FTC is looking to find out whether Facebook was trying to snuff out potential competitors before they could truly challenge the social media giant.
Facebook recently reached $5 billion agreement with the FTC over users' privacy violation in the Cambridge Analytica scandal that affected 87 million users.
Facebook CEO Mark Zuckerberg has already announced plans for convergence between Facebook, Instagram and WhatsApp.
"There's a lot more that we need to figure out before we finalize the plans. This is going to be a long-term project that I think will probably be to whatever extent we end up doing it in - a 2020 thing or beyond," the Facebook CEO had said earlier this year.
He said more than the commercial benefits of the chat integration between the apps, he was concerned about data encryption.
"The first reason that I'm excited about this is moving more to end-to-end encryption by default in more of our products. People really like this in WhatsApp. I think it's the direction that we should be going in with more things in the future," he noted.
"There are also a number of cases that we see where people tell us that they want to be able to message across the different services."
The Irish Data Protection Commission (DPC) has warned Facebook over its planned integration of chat services, asking the social media giant to provide it with an "urgent briefing" on the proposals.
"The Irish DPC will be very closely scrutinizing Facebook's plans as they develop, particularly insofar as they involve the sharing and merging of personal data between different Facebook companies," DPC had said in a statement.
According to Zuckerberg, the idea is to let people utilise the apps to enhance the experience.