Kanye West tweets that he is running for president in 2020

Kanye West says he is running for president.

The American rapper, who is a vocal supporter of U.S. President Donald Trump, announced on Saturday that he would run for president in 2020 in an apparent challenge to Trump and his presumptive Democratic rival, former Vice President Joe Biden.

"We must now realize the promise of America by trusting God, unifying our vision and building our future. I am running for president of the United States," West wrote in a Twitter post, adding an American flag emoji and the hashtag "#2020VISION".

It was not immediately clear if West was serious about vying for the presidency four months before the Nov. 3 election or if he had filed any official paperwork to appear on state election ballots.

The deadline to add independent candidates to the ballot has not yet passed in many states.

The music mogul first announced back in 2015 that he would run for the White House this year, but then he and his equally famous wife Kim Kardashian West cozied up to President Trump.

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At one meeting in October 2018, West delivered a rambling, profanity-laden speech in which he discussed alternative universes and his diagnosis of bipolar disorder, which he said was actually sleep deprivation.

Elon Musk, the chief executive of electric-car maker Tesla and another celebrity known for eccentric outbursts, endorsed West's Twitter post: "You have my full support!" he wrote.

If West is serious, it will be tough for him to get on the ballot even as an Independent this late in the race.