“Your round.”/“So are you, you fat bastard!” (bar joke)

An English joke features two blokes drinking at a pub. “Your round (of drinks—ed.),” says one. “So are you, you fat bastard!” replies the other.
 
“Your round” (of drinks) means something different than “you’re round” (a shape). The joke was posted to the newsgroup alt.tasteless.jokes on October 13, 1998. Authorship is frequently credited to British prop comedian Tommy Cooper (1921-1984).
 
“Two oranges walk into a bar. One turns to the other and says, ‘Your round’” is a similar joke.
 
     
Wikipedia: Tommy Cooper
Thomas Frederick Cooper (19 March 1921 – 15 April 1984) was a British prop comedian and magician. Cooper was a member of the Magic Circle, and respected by traditional magicians. He was famed for his red tarboosh, and his appearance was large and lumbering, at 6 feet 4 inches (1.93 m) and more than 15 stone (210 lb; 95 kg) in weight. On 15 April 1984, Cooper collapsed with a heart attack on live national television. He died soon afterwards.
 
Google Groups: alt.tasteless.jokes
Two Fatties
S
10/13/98
Two fat blokes in a pub, one says to the other “your round.”
The other one says “so are you, you fat bastard!”
 
24 June 1999, The Herald (Glasgow, Scotland), Tom Shields and Ken Smith column, pg. 19:
KEEP up the Tommy Cooper jokes, you say. So here’s one more. Two fat blokes in a pub, one says to the other: “Your round.” The other one says: “So are you, you fat bastard.”
     
Google Groups: alt.fan.caesar-geezer
Tommy Cooper one liners:
Trouble
8/30/99
Two fat blokes in a pub, one says to the other “Your round.” The other one says “So are you, you fat bastard”
 
Google Books
Adult Only Blonde Jokes:
Guaranteed to Make You Giggle!.
By Jasmine Chan
Dingley, Vic.: Hinkler Books
2004
Pg. 97:
Two fat blondes are sitting in a pub.
One says to the other, Your round.’
And the other replies, ‘So are you, ya fat bastard!’
 
Google Books
Man Walks Into a Bar:
Over 6,000 of the Most Hilarious Jokes, Funniest Insults and Gut-Busting One-Liners
By Stephen Arnott and Mike Haskins
Berkeley, CA: Ulysses Press
2007
Pg. ?:
Two fat guys are in a bar. One says to the other, “Your round.” The other replies, “So are you, you fat bastard!”
 
Twitter
jokesbytweet‏
@jokesbytweet
Two fat blokes in a pub, one says to the other “Your round.” The other one says “So are you, you fat bast**d!”
9:13 AM - 19 Nov 2007
 
Google Books
The Humongous Collection of Funny Fat Jokes
By Melony Osterhoudt
Lulu Publishing (Lulu.com)
2013
Pg. ?:
Two fat blokes in a pub, one says to the other, “Your round.” The other one says “So are you, you fat pig!
 
Google Books
Bob and Brenda’s Joke Book
By Paul Gwilliam
Lulu Publishing (Lulu.com)
2013
Pg. ?:
Two fat blokes in a pub, one says to the other, “Your round.” The other one says “So are you, you fat bastard!”