According to two film interviewed by USA Today, Wahlberg had co-star approval in his contract, and refused to approve Plummer's casting in the film until he was paid a salary of over a million.
"What he said was, 'I will not approve Christopher Plummer unless you pay me.' And that's how he (expletive) them", the source said.
Since the story broke that Wahlberg chose to use the #MeToo moment to profit from reshooting the film, The Wrap has reported that reshoots weren't in Wahlberg's contract while they were in Williams's. Williams was reportedly paid less than $1,000 for the reshoots. But a source told USA Today that Wahlberg and Williams, both clients of William Morris Endeavor (the talent agency that negotiated the Spacey scandal payout for Wahlberg) had reshoots worked into their contracts.
Yet another source claims Wahlberg's lawyer rejected Plummer's involvement in a letter to the movie's financiers until Wahlberg got the additional money that he was demanding. Both actors had reshoots in their contracts and both actors were in Europe filming for approximately the same number of days. It's no wonder that he's remained silent over the issue of the reshoots, while Scott and Williams both took pay hits to make keep the budget for the reshoots around $10 million.
The actors union SAG-AFTRA responded to the initial reports of the pay inequality between Wahlberg and Williams by stating that they "are unambiguously in favor of pay equity between men and women in this industry and support every action to move in this direction".
This just sheds so much light on how these costars ended up getting paid so differently - but we have yet to hear directly from either actor about the massive gap.