Viettel, the largest mobile operator in Vietnam, has partnered with Fortumo for Google Play direct carrier billing in the country. As of this week, 55 million subscribers of Viettel can purchase apps, music and books from Google Play and charge the purchases to their phone bill.

Viettel is the first mobile operator in Vietnam to launch mobile payments on Google Play, according to a press release.

"The key reason for Viettel selecting Fortumo was our industry-leading technical platform that is capable of simultaneously handling large app stores as well as leading OTTs," said Gerri Kodres, chief business officer at Fortumo. "Additionally, Fortumo has been preferred choice for carriers in Asia because of our strong focus on the region and local presence. Vietnam is one of the fastest growing smartphone markets in Asia and we are proud to be chosen by Viettel as partner to launch Google Play."

Fortumo recently announced partnerships with the SingTel-backed video streaming service HOOQ and the world's largest digital newsstand, Magzter.