Access of undefined property

Hey guys,

still pretty new to AS3 so go easy on me :stuck_out_tongue:

I was wondering how do you change the properties of a movie clip from a class that isn’t the Document Class.

say I have text_mc on the stage and I want to change it’s alpha to 0
If I do text_mc.alpha = 0; inside of the Document Class it works fine but if I do it in another class I get this error
1120: Access of undefined property text_mc

any ideas how to fix this?