James Franco pranked his brother Dave Franco by posting a fake photo on his Instagram.com account suggesting the actor is in a relationship with Zac Efron.

The Spider-Man star shared an image of a fake article from a gossip website with the headline 'Zac Efron Dating Neighbors Co-Star Dave Franco'.

The actor captioned the image, "Effron (sic) and My brother, dating!!!!!! Congrats (sic), boys! I'm so happy for you!!!"

The fake image was taken from a fan's Instagram account and had been Photoshopped to look like a real gossip article.

Dave Franco starred alongside Efron in comedy movie Neighbors.