WhatsApp has started getting the Video Call option in the latest beta (v2.16.80) that is available through the Google Play Store.
When making a call, now you get two options, one for audio call and the other one for video call. As you can see in the image above, this feature is not active yet, but some users in a few other countries are able to make video calls.
Looks like this new feature needs to be activated from the server side, which might happen soon. This could roll out gradually, similar to the voice call that was initially available only for some users through invite, later it started rolling out for everyone. WhatsApp is also said to be working on ‘send group invites via links, QR codes and NFC tags’.