Updating to WhatsApp version 2.12.5 via Google Play does the trick. Once you’ve got the latest version, you’ll see a revamped interface with three tabs for calls, contacts and chats.
To place a call, tap the Calls tab and then the new call button at the top of your screen. Then, select a contact to ring them over WhatsApp.
The feature is slated to arrive on iOS in the coming weeks, said WhatsApp co-founder Brian Acton at Facebook’s recent F8 conference.