My weekend project is to install a ceiling ventilation fan and recessed light over the shower in our master bathroom. I have already purchased the fan and wet location luminaire. The issue as hand is figuring out how to wire these things.

The bathroom currently is serviced by a 20A branch circuit that also covers an adjacent bathroom. This is on a standard (not GFCI) breaker. The bathroom has a switch-operated vanity light and one 15A GFCI duplex outlet with no attached load (the GFCI outlet does not protect anything "downstream").

I understand that the shower light must be connected with GFCI protection. I'm not 100% sure about the fan (it will be installed in the middle of the room and not directly over the shower), but I figure it wouldn't hurt to have that GFCI protected, also.

Is it permissible/advisable to use the load side of the existing GFCI duplex to power the light and/or fan? It is conveniently located next to the desired location for the wall switches for the new light and fan. If so, this will save me the expense of a GFCI breaker and about 50 feet of Romex back to the service panel.

I want to make sure my installation is legal by code, but don't want to spend unnecessary money (I have lots of other projects that need done around here, too). Thoughts?