Mobile messaging service WhatsApp has announced today it will launch free voice calls by mid-year. Whatsapp co-founder and CEO Jan Kuom revealed the foray into voice calls on the opening day of the four-day World Mobile Congress in Barcelona, Spain.

“We are going to introduce voice on WhatsApp in the second quarter of this year. We’re adding voice to WhatsApp so people can stay in touch with friends and loved ones no matter where they are in the world.” He said.

WhatsApp, which was recently acquired by Facebook for $19bn, will initially bring the voice-calling feature to iPhone and Android before rolling rolling out to Windows Phone and Blackberry.