Attribute dependent textfield

[mostlyharmless]

Hello.

Im right now working on a new site and i need some help on a matter.

Ive got products that "clean" version and 1 where theres extra work (tekst) on it.

I can add the added price as an attribute for the extra work version, but since i need a text field on that one i added a textfield. 

And here is my question:

Is there a way to only have the textfield show up for the extrawork version, but not the clean one?

Hope someone has an answer.

/regards
Bo