VIDEO: Watch Robert De Niro Send Happy Birthday Greeting to Zac Efron's Girlfriend

'Dirty Grandpa' costars Zac Efron and Robert De Niro record a special birthday message for Zac's girlfriend in the all-new FUNNY OR DIE video!

Funny or Die is an Emmy-winning comedy video website founded by Will Ferrell and Adam McKay's production company, Gary Sanchez Productions, with original and user-generated content. Funny or Die contains exclusive material from a number of famous contributors (e.g.Judd Apatow, James Franco) and also has its own Funny or Die Team, which creates original material for the site.

Many clips on the site feature well-known actors (examples include Steve Carell, Charlie Sheen, Ryan Gosling,Patrick Stewart, Daniel Radcliffe, Sophia Bush, Mila Kunis, Hilary Duff, Adam West, James Van Der Beek, Jim Carrey, and Selena Gomez). Michael Kvamme, an aspiring young comedian, came up with a concept for a new kind of comedy site and the site was developed by Randy Adams. Videos are voted on by users of the site; those that are deemed funny stay, but those that are not "die" and are relegated to the site's "crypt".