Social media platform WhatsApp has rolled out a security fix to its 1.5 billion users worldwide after concerns were raised that hackers could inject spyware on to phones via the call function. 

The vulnerability allowed hackers to insert malicious software on phones by calling the target using the app.

The company, which is owned by Facebook, believes that a select number of users were targeted by an "advanced cyber actor" exploiting the app's voice calling feature.

WhatsApp has asked its users to update the latest version of the app and to also keep their mobile operating system up to date.

You can update the app to safeguard your smartphone by following these simple instructions: 

For iPhone 

Open the App Store and along the bottom and select updates. 

Any pending app updates will be listed here. 

Select "WhatsApp" and Update. 

For Android 

 Open the Play Store and tap on the three lines in the upper left corner. 

Select "My apps & games" from the menu. 

Select "WhatsApp" and Select Update.