In 1957, Jim Henson was approached by a Washington, D.C. coffee company to produce commercials for Wilkins Coffee. The local stations only had ten seconds for station identification, so the Muppet commercials had to be lightning-fast—essentially, eight seconds for the commercial pitch and a two-second shot of the product.
From 1957 to 1961, Henson made 179 commercials for Wilkins Coffee and other Wilkins products, including Community Coffee and Wilkins Tea. The ads were initially filmed at Rodel Studios in Washington D.C. The ads were so successful and well-liked that they sparked a series of remakes for companies in other local markets throughout the 1960s.
The ads starred the cheerful protagonist Wilkins, who liked Wilkins Coffee, and the grumpy Wontkins, who hated it. Wilkins would often do serious harm to Wontkins in the ads—blowing him up, stabbing him with a knife, and smashing him with a club, among many other violent acts.
Wilkins and Wontkins were generally the only characters in the commercials, though on rare occasions, such critters as a Muppet whale or baby birds would appear. Company owner Mr. Wilkins was also invoked more than once.
The characters proved so popular that in June 1958, the company offered vinyl puppets of Wilkins and Wontkins through the mail for $1.00 and a coffee can label. The offer on the can said, "Hey Kids! I'm Wilkins—he's Wontkins—you see us on TV!" Obviously, Wilkins Coffee and Henson knew that the Muppet characters had kid appeal, although this doesn't seem to have had any effect on the use of violence and terror in the ads.
The only time Wontkins was caught drinking a coffee that was not Wilkins was in the 1958 "Steamroller" ad.
Here's one of the first Wilkins Coffee ads:
#1A: Coffee Break
Wilkins: Coffee break! Want a cup of Wilkins?
Wontkins: No thank you.
*Wilkins pushes Wontkins to cause it to fall down*
Wilkins: Now all of our workers drink Wilkins.
*Wontkins bonks off-screen*