Was the actor Seth Rogen in the film Step Brothers?

Answer 1

Yes he was. The actor Seth Rogen does appear in the film called The Spiderwick Chronicles.
He plays the voice of Hogsqueal.

The Spiderwick Chronicles was released in the year 2008.

Answer 2

Yes he was. The actor Seth Rogen does appear in the film called Step Brothers.
He is credited with playing the role of "Sporting Goods Manager".

Step Brothers was released in the year 2008.

Answer 3

Yes, the actor Seth Rogen does appear in the film called This Is the End.
He plays the role of Seth Rogen (himself).

This Is the End was released in the year 2013.