Kamala Harris will become the first women to be granted presidential power as US President Joe Biden undergoes a routine medical procedure.
The White House confirmed that Mr Biden would temporarily hand over power to his Vice President while he is under anaesthesia for a colonoscopy as part of his annual physical.
Ms Harris has already made history as the first woman and person of colour to become Vice President.
No woman has ever been President in the country's nearly 250-year history.
White House Press Secretary Jen Psaki said: "Following the process set out in the Constitution, President Biden will transfer power to the Vice President for the brief period of time when he is under anaesthesia.
"The Vice President will work from her office in the West Wing during this time."
Presidential power has been transferred to the vice president before, when President George W. Bush had colonoscopies in 2002 and 2007, she said.
Mr Biden, who turns 79 on Saturday, was set to undergo his first annual physical as President at the Walter Reed military hospital outside of Washington on Friday.
He is the oldest person to have served as President.
Mr Biden has vowed to be more transparent about his health than his predecessor Donald Trump and the White House has said he will authorise details from his medical report for publication.
Mr Trump was criticised for being secretive about his health, including a visit to Walter Reed in 2019 for an undisclosed reason that a former press secretary, Stephanie Grisham, later revealed was for a colonoscopy.
He was admitted to hospital with Covid-19 less than a month before the 2020 presidential election but conflicting statements were given over the severity of his illness.
The then-president was also criticised by medical experts for his decision to greet supporters from a car while driving past the hospital as he was being treated for the virus.
