Christopher Plummer says he isn't really "replacing" Kevin Spacey in All the Money in the World, but rather creating a whole new role, in a way.

Following director Ridley Scott's decision to recast and reshoot all of Spacey's scenes in the upcoming J. Paul Getty biopic following multiple allegations of sexual harassment against Spacey, Plummer stepped in to take on the role of the infamous billionaire oil tycoon.

ET caught up with Plummer on Sunday at the premiere of his upcoming film The Man Who Invented Christmas, and spoke with the 87-year-old screen legend about the unprecedented move to recast the star of a movie after the film had been completely finished.

"It isn’t replacing. In a funny way it’s starting all over again because it’s going to be different, naturally," Plummer explained. 

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Scott, along with the film's executive producers, decided to cut Spacey out of the film entirely after the actor was accused of sexual harassment and misconduct by numerous people -- some of whom claim to have had sexual encounters with the actor when they were underage. 

"The situation is very sad, because he’s such a talented guy. The whole circumstance is sad," Plummer said. "But I’ve got to forget that and go and do it, because it’s a very well written script and Ridley has been very good."

The Oscar winner also explained that he felt no real hesitation at taking on the role after Spacey, because he had already been in talks to play Getty before the House of Cards actor was cast.

"At one point we were discussing doing it in the early days," Plummer recalled. 

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Despite the cost of reshoots and the time it will take, Scott has been outspoken about wanting to have the film ready for its initial release date of Dec. 22.

"Yeah, it's quite a push," Plummer said of the reshoot schedule, adding that they plan to start shooting next Monday.

While fans wait to see the how the storied thespian takes on the role of the infamous American business magnate, Plummer is starring in The Man Who Invented Christmas as a different iconic rich misanthrope -- Ebenezer Scrooge --  and he said the chance to play such a famed literary character was "marvelous."

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"It’s a great classic role. He’s a wonderful villain and then he's a heart of gold suddenly," Plummer reflected. "It couldn't be better!"

The Man Who Invented Christmas -- which follows real-life author Charles Dickens as he struggles to pen his celebrated classic A Christmas Carol -- comes out Nov. 22.

Reporting by Rande Iaboni.