Will Smith has turned his back on pal Tom Cruise's efforts to convert him to Scientology because he doesn't want to upset his late grandmother. Smith admits he has spoken with Cruise about the church the MISSION: IMPOSSIBLE actor is a fervent campaigner for, but he could never follow writer and thinker L RON HUBBARD's belief system. He says, "I've talked to Tom about it - (there's) lots of incredible, wonderful concepts (but, my wife) JADA (PINKETT SMITH) and I don't necessarily believe in organised religion. "I was raised in a Baptist household and my grandmother would get up out of her casket (if I became a Scientologist)." The Smiths were among the special guests at Cruise and Katie Holmes' Scientology wedding ceremony in Italy last month (NOV06).