LOS ANGELES (AFP) ― Marilyn Monroe, who notoriously had an affair with John F. Kennedy, apparently believed she was going to marry the president, even phoning the White House to tell his wife.

The story, reported in a new book out Tuesday by journalist Christopher Andersen, asserts that Jackie Kennedy even told Monroe that the screen siren was welcome to take over her role as first lady.

“And you’ll move into the White House and you’ll assume the responsibilities of first lady, and I’ll move out and you’ll have all the problems,” she reportedly told Monroe.

The incident is just one layer of the complex marriage in the year before the president was assassinated, according to the new account.

The book chronicles how Jackie begged to stay by her husband even in the face of a nuclear strike, how the couple withstood the death of their newborn son Patrick, as well as how they weathered JFK’s many extramarital affairs.

It aims to answer whether the pair, 33 and 46 when JFK was killed, who captured the hearts of the nation, truly loved one another.

According to Andersen’s research, Jackie was well aware of her husband’s many infidelities, but was only upset over Marilyn ― not because of the affair, itself, but because the first lady feared the scandal set her up for public ridicule.

And when the Cuban Missile Crisis was brewing in 1962 amid rising Cold War tensions, Jackie protested plans to send her and the children to shelter away from Washington in the event of a nuclear attack.

“Please don’t send me anywhere if anything happens, we’re all going to stay right here with you,” she said.

“I want to die with you, and the children do too ― rather than live without you.”