Best Actress nominee Ruth Negga, Hamilton creator Lin-Manuel Miranda and supermodel Karlie Kloss were among the stars who sported blue ribbons while walking the red carpet at the Oscars.

So why is everyone so blue?

It’s actually a low-key political statement. Here’s what you need to know about it.

From left: Ruth Negga, Karlie Kloss and Lin-Manuel Miranda. Photo: Getty

What do the ribbons mean?

They’re in support of a campaign by the American Civil Liberties Union (ACLU).

According to its own website, the ACLU “works in the courts, legislatures and communities to defend and preserve the individual rights and liberties guaranteed to all people in this country by the constitution and laws of the United States”.

African-American director Berry Jenkins, who won his first Oscar for Best Adapted Screenplay for Moonlight, also donned a blue ribbon for his acceptance speech.

“All you people out there who feel like your life is not reflected, the Academy has your back, the ACLU has your back,” Jenkins said.

Significantly, there’s one person the ACLU has had in its sights of late: US President Donald Trump.

OK. Why Donald Trump though?

The ACLU has taken significant issue with many of President Trump’s actions since he took office.

From his immigration order:

Our take – Trump's "extreme vetting" of Muslims goes against the Constitution, freedom of speech and religion: https://t.co/roaASx0Wrv pic.twitter.com/8kYsqiSOHc

— ACLU (@ACLU) January 27, 2017

To his comments about the American press:

The remarks by President Trump's press secretary ring of McCarthyism and will lead to losing legal battles. Our response below. pic.twitter.com/G4Nt6k4XeQ

— ACLU (@ACLU) January 22, 2017

There hasn’t been a lot Mr Trump has done that the ACLU has agreed with.

It’s become the organisation and voice for many who oppose the Trump administration.

Supporters have been putting their money where their mouth is, pouring a whopping $US24 million ($A31 million) in online donations into the ACLU coffers since Donald Trump announced his executive order on immigration, according to the New York Times.

For context, the ACLU raised $US3.5 million ($A4.5 million) during all of 2015.

Thank you @BandryBarry. And yes, to all who don't see a mirror of themselves, Barry Jenkins is right, the ACLU does have your back. #Oscars pic.twitter.com/MuSBLKjuXY

— ACLU (@ACLU) February 27, 2017

Karlie’s dilemma

For Karlie Kloss, the blue ribbon made a particular statement. The model is dating Joshua Kushner, the brother of Donald Trump’s son-in-law and senior advisor, Jared Kushner.

Joshua recently visited the White House with his older brother, shortly after attending the Women’s March against the Trump administration in Washington.

https://www.instagram.com/p/BPlQuThjYwz/?hl=en

– with ABC