Viber offers mobile messaging and voice calls across devices and is similar to Skype and WhatsApp. It was launched three years ago and was acquired by Rakuten in February.
Hardy, who has been brought on board as CMO as the platform pursues global expansion plans, is tasked with establishing a global marketing office in London, including a UK PR team.
He will lead brand development, marketing strategy and campaign development, overseeing existing local marketing teams in Brazil, India, the Philippines, and Vietnam and the creation of teams in new international territories.
Hardy was previously marketing director for Simon Cowell’s Syco Entertainment and European marketing director of PlayStation and most recently was group digital director at Bauer Media where he launched its first digital-only media brand The Debrief.
Viber CEO Talmon Marco said: "We have built an incredible platform since Viber launched just over three years ago and we have grown an enthusiastic and engaged community of users. Now we want to reach an even larger community and expand and deepen our presence in strategic global markets."