Leave it to Nick Gombash of Hungary Exchange to trace Lady Gaga's roots - especially since she has both Sicilian & German roots!  Lady Gaga was born Stefani Germanotta and whose parents both shared Italian ancestry.  

Lady Gaga's paternal grandfather was Joseph Anthony Germanotta. He was born to Italian immigrants from Naso, Messina, Sicily..

 While this family is from Malta they seem to have roots in Sicily so worth taken a look at.   Some very interesting genealogies  posted dating back to the 1300's which are linked to several noble families such as Gatto, Aragona, and Ragusa to name a few.

 The Noble Family of Solimella, who held in fief the garden of Gomerino (pre-1318), also acknowledged as Milite in a letters patent relative to the Captaincy of Malta.  This family is listed as a noble family in “Descrittione di Malta” (1647)....

If you have Waldensian roots then you might want to check out the website at Finding Your Waldensian Ancestor.  Looks like the author(s) did quite a bit of research on the subject as the site is very nicely laid out and is user friendly.  There are several areas to explore which include an introduction to the non profit group Piedmont Families Organization, a brief historical sketch of the Waldensian's, reading list and family researchers.

They have compiled a list of known  Italian/Waldensian surnames based  on the book by Osvaldo Coisson, I Nomi di Famiglia delle Valli Valdesi  - some of which surprised me.  You may also submit Waldensian surnames if yours is not already listed.  Lots of good information.  Worth a read.