Kennedy, 69, the son of assassinated 1968 presidential candidate U.S. Senator Robert F. Kennedy, filed papers with the Federal Election Commission on Wednesday.

Marianne Williamson, the self-help guru who warned of the "dark psychic force" unleashed by Republican President Donald Trump, launched a Democratic presidential bid for 2024 in March, calling for "justice and love."

A longtime vaccine skeptic, Kennedy was tapped in 2017 to oversee a presidential panel to review vaccine safety and science at the request of U.S. President-elect Donald Trump, a move that drew immediate criticism from scientists and public health experts who feared it would legitimize skeptics of childhood immunizations.

In 2021, Instagram removed Kennedy's account after he repeatedly shared debunked claims about COVID-19, in violation of its policies on the coronavirus pandemic.

The environmental lawyer, a member of the storied American political dynasty, was a nephew of assassinated President John F. Kennedy.

Kennedy hinted at his presidential ambitions in a Twitter post last month asking for help in deciding whether he should run for the White House.

 "If it looks like I can raise the money and mobilize enough people to win, I’ll jump in the race," he wrote.

"If I run, my top priority will be to end the corrupt merger between state and corporate power that has ruined our economy, shattered the middle class, polluted our landscapes and waters, poisoned our children and robbed us of our values and freedoms."