“I walked into a bar and ordered a double…” (bar joke)

“A guy walks into a bar…” is a typical form of what has been called the “bar joke.” A pun on the terms “double martini” and “body double” is:
 
“I walked into a bar and ordered a double. The bartender brought out a guy who looked just like me.”
 
The joke has been cited in print since at least 2005 and has been printed on an image.
 
     
Google Books
Guy Walks Into A Bar…:
501 Bar Jokes, Stories, Anecdotes, Quips, Quotes, Riddles and Wisecracks
By Michael Lewis
New York, NY: Black Dog & Leventhal Publishers, Inc.
2005
Pg. 19:
I walked into a bar and ordered a double. The bartender brought out a guy who looked just like me.
 
Twitter
Blk Thai‏
@Blk_Thai
I walked in a bar and ordered a double.  The bartender brought out a guy who looks just like me.  Sleep Well All!
http://tinyurl.com/n8dh2v
10:13 PM - 13 Jul 2009
 
Twitter
GOT MY EYES ON YOU!‏
@nystyleman
I walked into a bar and ordered a double.The bartender brought out a guy who looked just like me! Laughitout!
11:48 AM - 11 Aug 2010
     
Twitter
Comedian MizT‏
@MizTcomedy
I walked into a bar and ordered a double. The bartender brought out a guy who looked just like me.#lol #jokes #MizT
6:16 AM - 15 Oct 2015
 
Twitter
Alan S Harrell‏
@ashtexas
I walked into a bar and ordered a double.  The bartender brought out a guy who looked just like me.
5:39 PM - 12 Nov 2015