Millions of mobile phones and tablets will make a loud siren-like sound and vibrate for around 10 seconds at 3pm on Sunday 7 September.
You will receive a text message, but you do not need to do anything.
The national test of the Emergency Alerts system has been set-up to improve the way society prepares for and responds to emergencies.
The message will be sent to all 4G and 5G phone networks in the UK, and will make it clear that it is a test and no further action is needed.
This will be the second test of its kind, to make sure the system works and to familiarise the public with the alerts.
This message was first shared with Grayshott Parish Council via East Hampshire District Council. To see lots more interesting news, sign up to their newsletter here:
