Unanswered: Nerd uses alien prank to fool bully...

Hello, there will be spoilers ahead:-
here's a memory thats been nagging the brain for a while. I saw this mid 80's. Not sure if it was an american movie or TV show but what i remember was a school nerd getting bullied. So the nerd comes up with a plan to dress as an alien and film himself sending a video message as if he is contacting the earth (not sure if he spoke english or alien) but he made sure the bully picked up the transmission on his tv, or other device, and the bully was convinced that he was speaking to an alien and told everyone but nobody believed him.
**spoilers ahead**
So the bully arranges with the alien to contact him at a certain time so there was witnesses and everyone at school turned up. So there's a huge crowd and the 'alien' appears on screen while the bully shouts to everyone "see, i told you the alien was real" etc and then the nerd removed his alien mask to reveal himself & everyone laughed at the bully for being stupid and gullible for falling for a prank...
Any ideas?
Thanks