Can I activate a DLC on Steam without owning the base game?

You often receive DLCs on Humble Bundle or similar sites without owning the base game. Can I activate them without worries?

For sure I can't play the game, but assuming that you are waiting for a sale on the base game for example, it would be the easiest method just to activate it.

Maybe it is also depending on which game, does anybody have experience with this issue?

Solution 1:

If you don't own the base game, Steam won't allow you to activate an add-on (eg, DLC) for it. You'll need to own the base game on Steam first.

Edit: The error you get is as below:

Solution 2:

You cannot activate it without owning the base game on steam. Steam will show you a message that you need to purchase the base game first.