Actor Jon Hamm was caught on camera at Game 3 of the World Series between the Chicago Cubs and the Cleveland Indians wearing a hat that likely upset a number of Cubs' fans, and the images soon went viral.

Hamm, 45, best known as advertising executive Don Draper on the television program 'Mad Men', was not wearing an Indians cap either.

A grinning Hamm was seen thoroughly enjoying the Cubs' 1-0 loss that evening, as he wore his St. Louis Cardinals hat, FOX Sports reported.

A St. Louis native, Hamm is known to be a super fan of his hometown team.

It may have been simple coincidence that Hamm wore his Cardinals' cap, but during the regular season, the Cubs and Cards are bitter rivals.

And, judging by the internet's reaction, Hamm's hat choice caused a stir nonetheless.

One sportswriter pointed out that the logo on Hamm's hat dates back to the early 1900's, the last time the Cubs won the World Series.

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