Reese Witherspoon learned the hard way -- if you have to tell someone, "Do you know who I am?" ... you're NOT as famous as you think you are, this according to David Spade.
Spade was leaving Boa Steakhouse in Hollywood last night when we asked if there's ever a good time for a star to drop the "I'm a really big deal" schtick ( a la Reese) ... and the "Rules of Engagement" star gave it to us straight.
"If you have to explain to someone you're famous, then you're technically not that famous."
Hey Reese Witherspoon ...
YOU'RE NOT THAT FAMOUS!
4/23/2013 7:40 AM PDT BY TMZ STAFF
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