For example, who knew that future "Office" leading man John Krasinski appeared briefly in David Mamet's "State and Main?" Or that Zach Braff's first role was in "Manhattan Murder Mystery?" Speaking of Woody Allen, Sharon Stone was the "pretty girl on train "in his 1980 movie "Stardust Memories," and Woody himself made his acting debut opposite Peter O'Toole in 1965's "What's New Pussycat?"
You can check out their debuts, as Robert De Niro's, Sylvester Stallone's and more, in the video above.
(On a film nerd note: Jack Nicholson's first role was actually in 1958's "The Cry Baby Killer," but since he's so much fun as an eager, masochistic dental patient in "The Little Shop of Horrors," we'll overlook the fact that the video editors included it in the mashup.)