Separated at birth?

When I was watching the Golden Globes a few weeks ago, I was shocked to see Foo Fighters' frontman Dave Grohl take the stage to receive an award for Best Screenplay for Up in the Air. Then I realized it was actually Jason Reitman, the writer/director of the film.

Fun fact: Jason Reitman is the son of Ivan Reitman, director of films including Ghostbusters, Stripes, and Kindergarten Cop.