Emily Blunt Scolds John Krasinski for Wearing Red Sox Hats in England

'No one wears baseball hats in England,' she told Stephen Colbert.

Emily Blunt and Stephen Colbert

Photo by Scott Kowalchyk / CBS

Emily Blunt has a friendly reminder for Americans who plan on traveling to England: leave the baseball caps at home.

The Girl on the Train star chatted about the fashion faux pas on Thursday’s episode of the Late Show with Stephen Colbert. Blunt explained that, while Americans are pretty welcoming towards people from the U.K. and their outfit choices, the feeling isn’t exactly mutual.

The actress also revealed that her husband and noted Boston sports fan John Krasinski has a tendency to make the fashion mistake, which is why he gets treated so badly by the staff at the cafe near her old flat.

“He said, ‘They’re always so horrible to me,'” Blunt told Colbert. “I went, ‘Take your baseball cap off. That’s why. No one wears baseball hats in England. You look so American.'”

She added that they were much nicer to him after he stopped wearing his hats, most likely of the Red Sox variety.

Judging by his Instagram feed, Krasinski does have a tendency to wear baseball caps all the time, whether he’s doing a social media challenge with his dog or even reuniting with his old The Office pal Jenna Fischer.

Krasinski should probably listen to his wife. She is going to play Mary Poppins after all.

Check out more from Blunt’s chat with Colbert below.