Hilary Duff's Halloween costume has horrified her fans, and they are demanding an apology.

Every year, there is one.

Actually, most years, it’s more like ten.

Every Halloween, despite the ongoing discussion around appropriate costumes, there are celebrities who don’t seem to get the message.

The first person (because we are sure there is more to come) to make headlines this year for their insensitive costume is Hilary Duff.

Attending the Casamigos Halloween Party with her boyfriend, Jason Walsh, Duff dressed as a sexy pilgrim beside Walsh, who was a ‘chief’ native American Indian.

The Huffington Post first uncovered the photos, pointing out how culturally insensitive the costumes were.

"Dressing up as a Native American/pilgrim duo would be incredibly offensive in any year, considering the legacy of violence wrought upon native communities since the founding of this country," the Huffington Post wrote.

Backlash has been fierce on social media with one person writing, "If he [Walsh] wanted to be authentic he could have dogs set on him, or pepper sprayed."

Do you want a Halloween costume that won't offend people? Try these. (Post continues after audio.)

The harm of the costume is even worsened by protests that are occurring across American with Native Americans fighting the construction of a pipeline in North Dakota.

The project has the potential to contaminate the water of the surrounding areas and damage their sacred land.