How to effectively light a white background with only 2 lights.

How to effectively light a white background with only 2 lights. I need to photograph a set of clothes with a model in the studio. The idea is that we have 2 lights with continuous light and softboxes. I initially thought that we would have a Key light and a fill light, but to get High Key photos from what I see we need to light the background as well. Can I bring another light if necessary, such as an ideal set up?