Facebook-owned messaging service WhatsApp is testing video calls for some beta users, more than a year after it rolled out voice calls.

Some Android users who have joined WhatsApp's beta program are reporting the ability to make video calls, Android Police reports. Screenshots show that tapping the call button or contact card brings up a dialog with voice and video as options.

The person on the other end also must be a beta user with the voice-calling feature enabled. If not, the call will revert to voice only, according to Android Police.

The feature's availability seems to be random at this point. PCMag wasn't able to access it today from an account that participates in the Android beta program. Android Police and others report success forcing video calling to activate by wiping app data and logging in again.

A Facebook spokesperson declined to comment on the video-calling feature. Assuming the company plans to roll it out to all users, that process could take a while based on WhatsApp's historical schedule for major feature rollouts. Reports that the app was adding voice calling surfaced in 2014, but it wasn't until this March that all Android users had access to it. The iOS rollout of voice calling was completed a month later.

Part of the long development timeline may be related to Facebook Messenger. WhatsApp's parent company has invested heavily in its flagship messaging client. The Messenger app got video calling in 2015, and reports surfaced this week that Facebook was adding the feature to the Windows 10 app.

This article originally appeared on PCMag.com.