Using fondant and buttercream together?

[debbs072374]

I plan on making a 3 tiered square cake and have a question about fondant. I will most likely be using buttercream frosting for the cakes (unless I convince the person I'm making for otherwise) and I'll be doing ribbons around the bottom of all 3 tiers in fondant. Is there any problem with this plan? I know how fondant works on an entire cake but I haven't combined the two just for ribbons or bows.

Thanks