USA: The massively popular mobile messaging app now lets you communicate with friends through your laptop or PC for the first time - unless you have an iPhone.

 WhatsApp has extended its service so you can continue conversations you started through the mobile app when you are browsing the internet on a laptop or PC.

The web browser tool mirrors the conversations and messages you have on your mobile device - so all of the messages still live on your phone.

Unfortunately if you are an iPhone user, you won't be able to use the messaging service on your laptop due to “Apple platform limitations”, according to WhatsApp.

An iOS version is supposedly coming, but there's no clear time-frame for launch at this stage.

It will work for anyone with an Android, BlackBerry, Windows or Nokia S60 device - although you will need to upgrade to the latest version of WhatsApp.

To get started, you need to visit web.whatsapp.com using Google's Chrome browser and it will show you a QR code.

You then need to open up the menu in the WhatsApp app on your phone and click on the "WhatsApp Web" button. This will allow you to use the phone’s camera to take a picture of the QR code and this will allow you to start seeing your messages while you surf the web on your laptop or PC.

At the same time, WhatsApp has also banned an unofficial third-party Android app called WhatsApp Plus.

Anyone trying to use the unofficial app will get locked out of the service for 24 hours over concerns that it might lead to a leak of personal data - much like what happened with Snapchat.