Does Graphics.DrawTexture(...) have to be called from OnGUI()?

I'd like to Graphics.DrawTexture As I would use GUI.DrawTexture(...).

However I was wondering If I can use Graphics.DrawTexture(..) outside of OnGUI. (I don't want to use OnGUI Ultimately is the reason)

[edit] I should add... I have tried using it in Update() and It didn't work. So I'm guessing the answer is no, however someone may point out something I might have missed...

I basically want to be able to paint to a particular rectangle in screen coords without using OnGUI();

Try calling it from OnPostRender instead