Hilary Duff and her boyfriend have upset a lot of people with their controversial choice in Halloween costumes.

Dressed as a ‘sexy’ Pilgrim and a Native American, the pair posed for cameras at a Halloween party and the internet immediately took notice.

People Are Mad At Hilary Duff And Her BF For This Native American Costume https://t.co/7eOS4HqL4Q pic.twitter.com/y2haz7C366

— BuzzFeed News (@BuzzFeedNews) October 30, 2016

While the occasion would normally have people talking about Duff’s first public appearance with her new man, Jason Walsh, instead talk turned to just how inappropriate their costumes were.

Labelled “insensitive and ignorant” people were quick to tweet and blog about how cultural appropriation was most definitely NOT appropriate for a Halloween get up.

No @HilaryDuff Traditional dress is not a costume and you being dressed as a pilgrim proves to me how insensitive and ignorant you are. https://t.co/0NvP6DD79I

— LOOKING FOR CL'S EP (@hahannah14) October 29, 2016

The outfits hit a sore point with thousands of Native Americans currently protesting the construction of the Dakota Access Pipeline in the states.

Following ten months of protests, a police raid this week saw more than 100 people arrested.

This morning the star took to Twitter to apologise for the gaffe.

Writing to fans, she admitted the costume was poorly thought out.

I am SO sorry to people I offended with my costume.It was not properly thought through and I am truly, from the bottom of my ❤️sorry.

— Hilary Duff (@HilaryDuff) October 30, 2016

It comes as Chris Hemsworth publicly apologised for his own Native American costume on Instagram.

Sharing a snap showing his support for protesters, he wrote he also wanted to take the chance to apologise.

“Last New Year's Eve I was at a "Lone Ranger" themed party where some of us, myself included, wore the traditional dress of First Nations people,” he wrote.

Standing with those who are fighting to protect their sacred land and water. #nodapl #waterislife #mniwiconi @taikawaititi I would also like to take this opportunity to raise something that has been bothering me for sometime. Last New Year's Eve I was at a "Lone Ranger" themed party where some of us, myself included, wore the traditional dress of First Nations people. I was stupidly unaware of the offence this may have caused and the sensitivity around this issue. I sincerely and unreservedly apologise to all First Nations people for this thoughtless action. I now appreciate that there is a great need for a deeper understanding of the complex and extensive issues facing indigenous communities. I hope that in highlighting my own ignorance I can help in some small way.

A photo posted by Chris Hemsworth (@chrishemsworth) on Oct 27, 2016 at 6:49pm PDT

“I was stupidly unaware of the offence this may have caused and the sensitivity around this issue. I sincerely and unreservedly apologise to all First Nations people for this thoughtless action.

“I now appreciate that there is a great need for a deeper understanding of the complex and extensive issues facing indigenous communities.

“I hope that in highlighting my own ignorance I can help in some small way.”