In 1998, an American fan met Toshiyuki Nishida in Tokyo, and he gave her his autograph. See the Meeting Pigsy in Tokyo! page for full details.
Here's the autograph:
Interestingly, this fan didn't know Toshiyuki Nishida as Pigsy from "Monkey"; he knew him as his Hamachan character from "The Diary of Crazy Fishing" series of films.
Back to the Monkey Autographs - Toshiyuki Nishida page