Actor Ian Somerhalder has warned fans not to post photos of their ballot for Tuesday's (06Nov12) U.S. presidential election because sharing such images can invalidate their vote.

Social networking sites have been abuzz with messages and pictures of celebrities like Beyonce and other U.S. citizens casting their votes for their respective candidates on election day, but the practice is deemed illegal in many states and the Vampire Diaries star, who has expressed his support for incumbent Barack Obama, fears the Democrat leader's re-election campaign could take a hit if the photo-sharing continues.

Alerting fans to the misdemeanour via, he writes, "Tell followers not to post pictures of their ballot results on Ig (Instagram). It will be considered as an illegal vote. Obama dropped 3%.

"Do Not Post Ballot Pictures!!!! Posting ballot pictures can make (your) vote illegal! No Posting Picture!!!!"