A Google statement said: “Video calling is the next best thing to being with someone in person, but too often it can be a frustrating or complicated experience.
“You shouldn’t have to worry about whether your call will connect, or if your friend is using the same type of device as you are. It’s no wonder that nearly half of us never make video calls on mobile.”
Google has been offering a video call service through Hangouts since 2013, but that is now being specifically tailored for business meetings.
Duo is the first of two new mobile apps from the American firm, with a messaging app called Allo set to be released over the next few months.
Allo features a robotic assistant who suggests automated responses to messages, or even pictures, sent by friends.