If you have a cellphone, it probably buzzed and beeped loudly Wednesday around 2:18 p.m. EDT.
That means today, more than ever, if you are attending a matinee, turn OFF your cell phone.
The test message from the previously unused alert system was originally scheduled for September but was pushed back to 2:18 p.m. EDT (1818 GMT) on Wednesday. "WEA includes a special tone (some describe it as quite loud) and a vibration, both repeated twice", FEMA writes on its official website.
The test has been scheduled to ensure that the alert system would work in the event of an actual national emergency.
The system was brought into being under the Integrated Public Alert and Warning System Modernization Act of 2015. The lawsuit said the alert system violates the First and Fourth Amendments by failing to give people the chance to opt-out.
FEMA stated that some phones may not get the message. Instead, they're from the USA government, and both are test messages.
The alert test, which is FEMA's first for the wireless emergency system - and is being coordinated with the Federal Communications Commission - made a sound similar to an Amber Alert or flood watch warning.
He said some people did not receive alerts on some devices during that test.
FEMA is committed to continuously improving the national alert and warning systems and supporting local authorities in getting effective and timely warning to people.
The WEA message will read: "Presidential Alert".
Federal Emergency Management Agency (FEMA), which will send the alert, explained that the text will be titled, "Presidential Alert". This test will look and feel similar to the monthly EAS tests sent out on TV and radio, and it will interrupt whatever you're watching for about a minute.
It's very similar to Amber Alerts, however unlike the noisy notifications that warn people in a particular area of a child abduction, people can not opt out of this one.
About 225 million electronic devices across the United States will wail and buzz Wednesday afternoon as the Federal Emergency Management Agency conducts an emergency alert test.
In January, after months of escalating exchanges between Mr Trump and North Korean President Kim Jong Un, the state's emergency personnel sent out an alert message reading, "BALLISTIC MISSILE THREAT INBOUND TO HAWAII".
It is unknown if Trump will attempt to misuse this power as a political tool to make announcements.
There are also those who question if President Trump would abuse the system. FEMA is exploring making the alerts available in additional languages.