The Academy has apologised for "unwarranted" abuse endured by Sacheen Littlefeather after a speech she made at the 1973 Oscars. The news comes almost 50 years after Littlefeather's speech, which she made on behalf of Marlon Brando to speak out about the depiction of Native Americans in Hollywood films.

The Academy Museum of Motion Pictures said on Monday that it will host Littlefeather, now 75, for an evening of “conversation, healing and celebration” in September. "I never thought I'd live to see the day I would be hearing this," Littlefeather told the Hollywood Reporter.

When Marlon Brando won Best Actor for his role in The Godfather in 1973, Littlefeather took to the Oscars stage, becoming the first ever Native American woman to do so. In her 60-second speech, she explained that Brando would not be accepting the award due to "the treatment of American Indians today by the film industry."

The event took place during the American Indian Movement's two-month occupation of Wounded Knee in South Dakota, and was televised live to 85 million people. Introducing herself on behalf of Brando, Littlefeather told the audience "that he very regretfully cannot accept this very generous award - the reasons for this being the treatment of American Indians today by the film industry and on television in movie re-runs, and also with recent happenings at Wounded Knee."

Many audience members booed the actress, then 26, off the stage. Westerns star John Wayne was reportedly furious and had to be restrained backstage by six security guards during the speech.

Oscars organisers have now said that Littlefeather's speech was the first political statement at the televised ceremony, marking the beginning of a trend which continues to this day. However, Littlefeather said she has been personally attacked, discriminated against, and mocked for her brief appearance at the awards ceremony.

Some media reports after the event claimed that the actress was not truly a Native American, but that she agreed to do the speech to further her career. Others speculated she might be Brando's mistress.

In issuing their apology to the actress, the Academy Museum shared a letter sent to Littlefeather in June by Academy President, David Rubin.

“The abuse you endured because of this statement was unwarranted and unjustified,” Rubin wrote. “The emotional burden you have lived through and the cost to your own career in our industry are irreparable. For too long the courage you showed has been unacknowledged. For this, we offer both our deepest apologies and our sincere admiration.”

Rubin went on to say that Littlefeather’s speech was “a powerful statement that continues to remind us of the necessity of respect and the importance of human dignity”.

In a statement, Littlefeather said it is “profoundly heartening to see how much has changed since I did not accept the Academy Award 50 years ago. Regarding the Academy’s apology to me, we Indians are very patient people – it’s only been 50 years! We need to keep our sense of humour about this at all times. It’s our method of survival.”

In a podcast released earlier this year with Jacqueline Stewart, a film scholar and director of the Academy Museum, Littlefeather spoke about what inspired her to speak out in at the ceremony.

“I felt that there should be Native people, Black people, Asian people, Chicano people – I felt there should be an inclusion of everyone,” she said. “A rainbow of people that should be involved in creating their own image.”

Littlefeather will sit for a conversation with producer Bird Runningwater, co-chair of the Academy’s Indigenous Alliance, at the Academy Museum event in September.