Trump transition live updates: Trump names longtime ally Brooke Rollins as secretary of agriculture

Dr. Mehmet Oz has been selected to serve as the administrator of the Centers for Medicare and Medicaid Services, Trump announced.

The agency is within the Department of Health & Human Services. The position requires Senate confirmation.

Trump indicated that Dr. Oz will work closely with Robert F. Kennedy Jr. to take on chronic diseases.

MORE | Trump chooses TV doctor Mehmet Oz to lead Centers for Medicare and Medicaid Services

Trump has announced Howard Lutnick as his commerce secretary pick.

The appointment requires Senate confirmation.

CEO of investment bank Cantor Fitzgerald, Lutnick has been serving as co-chair of the Trump Transition team alongside Trump's former Small Business Administrator Linda McMahon, spending the past two weeks at the Trump Transition War Room he has set up at Mar-a-Lago recommending and vetting potential candidates for Trump's administration officials.

Lutnick has frequently joined Trump on the campaign trail and hosted numerous fundraisers for Trump alongside some of the major Republican donors like John Paulson, Duke Buchan and Woody Johnson.

The billionaire businessman was also vying for the job of treasury secretary, sources said, competing against investor and hedge fund manager Scott Bessent, who has also been considered a top contender for the role.

Lutnick's aggressive push to be tapped as Trump's treasury secretary as he spent hours with the president-elect nearly every day as a co-head of the transition team had frustrated some close to Trump, sources said.

Elon Musk has been a close ally of Lutnick, publicly endorsing him for the treasury spot recently and often seen together at events, including at the AFPI gala last week.

He had donated $1 million to Trump's inaugural committee in 2017 and most recently donated $5 million to pro-Trump super PAC Make America Great Again Inc.

Lutnick has been a vocal advocate for cryptocurrency, speaking at the annual Bitcoin Conference in Nashville earlier this year where Trump and RFK Jr. also spoke.

Trump is expected to attend Tuesday's SpaceX launch in Texas, multiple sources told ABC News.

SpaceX said it is planning to hold the sixth integrated flight test of its Starship megarocket from its Starbase in Cameron County, Texas, on Tuesday afternoon.

SpaceX founder Elon Musk, who will co-lead the Department of Government Efficiency, has rarely left Trump's side since the election -- appearing in family photos with Trump at Mar-a-Lago and even traveling with him to New York for Saturday's UFC fight.

Trump frequently marveled at the intricacies of the SpaceX rocket launch while on the campaign trail.

"It was so exciting, so I'm watching it, and this monstrous thing is going down, right and it's coming down, it's first of all, doing all sorts of flips up in the air," Trump said at his last campaign rally of the cycle in Grand Rapids, Michigan.

Billionaire Elon Musk is throwing his support behind Matt Gaetz, President-elect Donald Trump's pick for attorney general, as allegations continue to surface surrounding what witnesses told the House Ethics Committee regarding the former congressman.

"Matt Gaetz has 3 critical assets that are needed for the AG role: a big brain, a spine of steel and an axe to grind," Musk wrote on X. "He is the Judge Dredd America needs to clean up a corrupt system and put powerful bad actors in prison."

"Gaetz will be our Hammer of Justice," he added.

Musk also directly addressed the allegations against Gaetz, stating that he considers them "worth less than nothing."

Musk's public support for Gaetz comes as the billionaire continues to play a large role in Trump's transition, as ABC News has previously reported.