know someone when

Etymology
From the formulaic phrase by which speakers begin reminiscence of now-famous persons.

Verb

 * 1)  To have known a famous person before he or she was famous.
 * 2) * 1915, "Interesting People: Charles Bullard: A Famous Photographer of Cats", in "The American Magazine"
 * His friends thought him crazy, as friends always think when a man has an original idea and acts on it. Now, when his friends speak of him they invariably add, "I knew him when—"