19 Celebrities Who Started As Extras
Although it isn't a written rule, an "extra" -- a background player in a movie or TV show -- usually has no spoken lines.
If a line, or a few lines, are spoken, the person is often referred to as a "bit player" instead of an extra. (If a major star or a "known" actor is an extra in a movie, their non-speaking appearance is called a "cameo.")
Many famous people such as Sylvester Stallone, Brad Pitt and Marilyn Monroe made one or more appearances as movie extras before they went on to bigger and better things.