Beer keg smashes Sydney motorist's windscreen

Dashcam footage has captured the moment a beer keg smashed into a motorist's windscreen as he drove down a busy highway.

The keg slammed into a car on Sydney's M4 road.

The footage, posted to Facebook group Dash Cam Owners Australia, shows the motorist driving down the right-hand lane before the keg comes - seemingly out of nowhere - to hit the vehicle. 

The video cuts out as a result of the impact. 

It is believed the keg was empty, but still caused significant damage.

The video has since gone viral, with Facebook users commenting on the impact of the keg gave them a fright. 

One user said, "It made me JUMP lmao."

The footage has been viewed 49,000 times on Facebook.