WhatsApp, the world's biggest mobile messaging service, intents to add voice calling feature to its free messaging service in the second quarter of 2014, as announced on Monday.
The move is aimed at enabling WhatsApp users to be able to make calls, just as they can now text messages.
The latest announcement answers some of the questions behind WhatsApp's recent purchase by Facebook for a price of $19 billion, Xinhua reported.
WhatsApp founder and chief executive Jan Koum, while addressing the opening day of the Mobile World Congress in Barcelona, Spain, confirmed the aim was to introduce voice calls, initially on the iPhone and Android.
Windows Phones and BlackBerrys will be included at a later date, he added.
"We are adding voice to WhatsApp so that people can stay in touch with friends and loved ones no matter where they are in the world," said Koum.
"We use the least amount of bandwidth and we have optimized it. We have made sure the quality is there," Koum said, adding there were no other plans to change his company in the new Facebook era.
"WhatsApp will continue to function as if it is an independent company without adding to its small staff of just 55 employees as the intention is for it to be able to remain as adaptable as possible."