Madonna, an outspoken critic of President-elect Donald Trump, has vowed to march with other women in Washington on Saturday.

The 58-year-old multimillionaire promised to join the 'Women's March' in the capital which takes place the say after Trump is sworn in as she launched another attack on him.

Speaking at the Brooklyn Museum in New York in a staged 'conversation' with Marilyn Minter, an American artist known for her use of hard-core pornography, she claimed his election meant 'we can only go up from here'.

'Elected for a reason': Madonna admitted there could be a purpose for the election of the new president - but said she was 'horrified' that Hillary Clinton lost

This is what a feminist looks like: Madonna leaving her 'conversation' at the Brooklyn Museum in New York with artist Marilyn Minter, known for her use of hard core pornography

Madonna had supported Hillary Clinton in the election and even offered to perform sex acts on people who voted for her, although she did not fulfill her promise then.

Dressed all in black with a shirt saying 'Femininst', she said of Trump: 'He's actually doing us a great service, because we have gone as low as we can go.

'We can only go up from here, so what are we going to do? We have two choices, destruction and creation. I chose creation.'

The discussion was moderated by author and poet Elizabeth Alexander, who performed a work at the first inauguration of President Barack Obama.

A clip of author James Baldwin, an inspiration of Madonna's, played before the talk, as did her 2013 short film 'Secret Revolution,' dedicated to people whose rights have been 'abused and denied'.

'This is the most frightened I've ever been,' Minter said. 'The most qualified candidate who ever ran was defeated by the most unqualified candidate who ever ran, and it's all because of misogyny.'

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Madonna said that while she was 'horrified' Trump won the election over Hillary Clinton, she now believes it was necessary.

'I do believe that Trump was elected for a reason, to show us how lazy and un-unified and lackadaisical and taking for granted we've become of our freedom and the rights that we have as Americans,' Madonna said.

'I feel like people forgot what was written in the Constitution.'

She added: 'They always say it's darkest before the dawn and I feel this had to happen to bring people together, so let's get this party started.'

The Women's March in Washington was originally called the Million Women's March but scrapped the title and is now expected to have around 80,000 attendees.

It wasn't all political talk. Madonna talked about her early days in New York, hanging with artists like Andy Warhol and Keith Haring, and how her kids are not the least bit impressed with her iconic career.

'They want nothing to do with it,' she said. 'I always say with my kids, every day is a small crucifixion.'

Madonna also explained why she considers herself a feminist.