A Facebook spokesperson has confirmed these developments explaining more on the rebranding.
"We want to be clearer about the products and services that are part of Facebook," they said.
Mark Zukerberg bought the photo-sharing app (Instagram) in 2012 and WhatsApp in 2014, and since then Facebook allowed these two applications to operate as independent entities.
The companies had their own managers, employees, and even separate workplaces. Facebook has taken steps in the past year to make WhatsApp and Instagram less independent.
According to Facebook, the change won't affect any of the apps' functions; it's merely cosmetic and won't alter the app names on the home screens.