The This Is The End star uploaded an image of a bogus article from a gossip website with the headline 'Zac Efron Dating Neighbors Co-Star Dave Franco'.
The elder Franco captioned the image, "Effron and My brother, dating!!!!!! Congrats, boys! I'm so happy for you!!!"
The fake photo was taken from a fan's Instagram account and had been augmented to look like a real gossip article.
As for Zac, he has been romantically linked to actress Michelle Rodriguez.