Former NBA star Charlie Villanueva, who's famously battled Alopecia, ripped Chris Rock for his Oscars barb about the autoimmune disease ... adding that he's "proud" of Will Smith for defending Jada Pinkett Smith. Villanueva took to Instagram to express his thoughts on the Smith-Rock altercation at Sunday night's Academy Awards ... saying as someone who's had to deal with Alopecia, he knows what Jada is going through. SUBSCRIBE -- http://tmz.me/j0hSW37 About TMZ Sports: Some of the best stories in sports have been off the field and we’re reporting on athletes from NFL, NBA, UFC, WWE, MLB and more! Subscribe to TMZ Sports on YouTube for the latest news, exclusive interviews, clips from TMZ Sports on FS1 and videos of your favorite athletes and celebs. Need More TMZ? TMZ Sports Website: http://tmz.me/jMBERbb LIKE TMZ on Facebook! http://tmz.me/9sGB00a FOLLOW TMZ on Twitter! http://tmz.me/9LeeNWQ FOLLOW TMZ on Instagram! http://tmz.me/ep7d8Bn TMZ on TV & TMZ Sports on FS1 Tune In Info: http://tmz.me/ccuirUZ TMZ is on iOS! http://tmz.me/ecOjgiH TMZ is on Android! http://tmz.me/pkwieRA Got a Tip? Contact TMZ: http://tmz.me/UsxYCvE Check out TMZ, TMZ Live, and toofab! TMZ: http://tmz.me/fPrTwZt Subscribe! TMZ: http://tmz.me/wONe5NO TMZ Live: http://tmz.me/GxCXCfl Subscribe! TMZ Live: http://tmz.me/cLxA82p Toofab: http://tmz.me/dsXztns Subscribe! toofab: http://tmz.me/VeVLMmi https://www.youtube.com/c/tmzsports