The re-shoots needed to replace Kevin Spacey with Christopher Plummer took eight days to film at a cost of $10 million. It also involved Mark Wahlberg and Michelle Williams having to return to the Rome set during the Thanksgiving holiday of 2017.
After Kevin Spacey was replaced by Christopher Plummer, director Sir Ridley Scott decided not to show Plummer any footage of Spacey in character, or even tell him how Spacey played the scenes. When finished, Scott found both performances to be quite different and equally effective in their own particular styles.
Christopher Plummer claimed he was prepared to replace Kevin Spacey as Jean Paul Getty on short notice because he had previously been considered for the role and had read the script. He had less than two weeks to memorize his lines, but did have the advantage of having met Getty in London at a couple of his parties during the '60s.
Mark Wahlberg had lost thirty pounds for his next film when he was asked to come back for re-shoots. His costumes had to be refitted.
On November 8, 2017, Sony and the film's production team unanimously opted to replace Kevin Spacey as Jean Paul Getty with Christopher Plummer. The decision was made just over a month prior to the December 22nd wide release. This was the second time Sir Ridley Scott was faced with drastic re-shoots during his career. He had previously almost had to abandon Gladiator (2000) due to the untimely death of Oliver Reed.