Dennis Christopher first came to recognition in the 1979 coming-of-age movie "Breaking Away". I liked his portrayal of the character 'Dave' and looked forward to seeing him in other movies. Some of his other prominent roles were in 1980's "Fade to Black" and 1981's "Chariots of Fire". Since that time, he has been in many other movies and tv shows.
I wrote to him in 1981, sending him two photos. He signed each and returned them promptly, within two weeks. The photos can be seen here and here. The latter he signed to me with only his first name, as if we were friends.