President Biden has another Democratic challenger vying for the presidency following Robert F. Kennedy Jr. filing paperwork with the Federal Election Commission on Wednesday.

Kennedy, the son of late former U.S. Attorney General Robert F. Kennedy and nephew of the late former President John F. Kennedy, is now the second Democrat to toss his hat into the race for the White House, joining spiritual advisor and author Marianne Williamson in seeking the party's nomination.

A Kennedy adviser wouldn't independently confirm his candidacy, but told Fox News Digital "the campaign will issue a statement tomorrow."

ROBERT F. KENNEDY ANNOUNCES COVID CENSORSHIP LAWSUIT

Democratic presidential candidate Robert F. Kennedy Jr.

Robert Kennedy Jr. speaks during "Fire Drill Friday" climate change protest on November 15, 2019 in Washington, DC. (John Lamparski/Getty Images)

Kennedy, a former environmental lawyer who describes himself as a lifelong Democrat and has faced criticism for his activism against the COVID-19 vaccine, sparked speculation about a potential White House run by visiting New Hampshire, which for a century has held the first primary in the presidential nomination race

"I’m thinking about it, and I’ve passed the biggest hurdle, which is my wife has green lighted it," Kennedy said at an event at the New Hampshire Institute of Politics, which for more than two decades has been a must stop for actual or potential presidential contenders from both major parties.

He took aim at the Biden administration and Democratic National Committee over the decision to move the New Hampshire presidential primary out of its position as the first in the nation primary. The state will now vote second in the DNC’s calendar, along with Nevada, three days after South Carolina, under the new schedule.

CALIFORNIA BOARD DENIES PAROLE FOR SIRHAN SIRHAN, MAN WHO ASSASSINATED ROBERT F. KENNEDY

Marianne Williamson

Self-help author Marianne Williamson speaks to the crowd as she launches her 2024 presidential campaign in Washington, Saturday, March 4, 2023. (AP Photo/Jose Luis Magana)

Ahead of the DNC's final approval of the schedule, Kennedy wrote an open letter to the committee, urging members to keep New Hampshire in the first spot because of the state's long history advocating for civil rights and election transparency. 

The DNC changed the nominating calendar in an effort to reflect more diversity in the Democratic Party, but Kennedy said that New Hampshire already showcases the diversity in America. As a swing state, Kennedy said, New Hampshire's "four electoral votes could decide the 2024 election." 

"Most importantly, New Hampshire runs the most secure and transparent election in America. It should be a model for our country at a time when we need it most," Kennedy wrote. 

President Joe Biden

U.S. President Joe Biden speaks at an event marking the 13th anniversary of the Affordable Care Act in the East Room of the White House on March 23, 023 in Washington, DC.  (Anna Moneymaker/Getty Images)

CLICK HERE TO GET THE FOX NEWS APP 

Biden has yet to announce whether he will run for reelection, however, the White House has repeatedly said Biden intends to run for a second term.

Fox News' Thomas Phippen and Paul Steinhauser contributed to this report.