In his controversial new memoir, "Apropos Of Nothing", he claims the young actor admitted as much to his sister.
In 2019, the 24-year-old starred in Allen's "A Rainy Day in New York". But when the #MeToo movement re-highlighted child sexual abuse allegations against the director, Chalamet announced that he would be donating all his earnings from the film to charity.
"All the three leads in 'Rainy Day' were excellent and a pleasure to work with," Allen wrote in his book, per Page Six. "Timothée afterward publicly stated he regretted working with me and was giving the money to charity, but he swore to my sister he needed to do that as he was up for an Oscar for 'Call Me by Your Name,' and he and his agent felt he had a better chance of winning if he denounced me, so he did."
He added: "Anyhow, I didn't regret working with him and I'm not giving any of my money back."
Chalamet would ultimately lose out on the Academy Award to Gary Oldman, for "Darkest Hour".
In his original Instagram post, Chalamet said contractual obligations prevented him from talking about the issue directly.
"This year has changed the way I see and feel about so many things; it has been a thrilling, and, at times, enlightening education," he wrote. "I am learning that a good role isn't the only criteria for accepting a job -- that has become much clearer to me in the past few months, having witnessed the birth of a powerful movement intent on ending injustice, inequality and above all, silence."
"I have been asked in a few recent interviews about my decision to work on a film with Woody Allen last summer," he continued. "I'm not able to answer the question directly because of contractual obligations. But what I can say is this: I don't want to profit from my work on the film, and to that end, I am going to donate my entire salary to three charities: TIME'S UP, The LGBT Center in New York and RAINN. I want to be worthy of standing shoulder to shoulder with the brave artists who are fighting for all people to be treated with the respect and dignity they deserve."
In addition to Chalamet, Rebecca Hall, Greta Gerwig, Ellen Page, Mira Sorvino and David Krumholtz all expressed recent regret over working with Allen.
"The fact these actors and actresses never looked into the details of the case (they couldn't have and come to their conclusion with such certainty) did not stop them from speaking out publicly with dogged conviction," Allen wrote in the book. "Some said it was now their policy to always believe the woman. I would hope most thinking people reject such simple-mindedness."
"More people should have said, I really don't know all the facts so I have to withhold my judgment. God forbid anyone should say, 'This accusation has been thoroughly investigated and found to be untrue.'"
He thanked the colleagues who did speak out in his defense, assuring them: "it's not something they will ever be embarrassed having done."
The memoir was finally released by Arcade Publishing on Monday after it was dropped by Hachette Book Group; staff there had walked out in protest, shortly after Allen's estranged son Ronan Farrow threatened to end his relationship with the publisher which had released his book "Catch And Kill" -- detailing his investigation into Harvey Weinstein's sex crimes.
In 1992, Allen was accused by his ex partner Mia Farrow of molesting her adoptive daughter Dylan Farrow, eight months after she learned Allen was having an affair with another of her adoptive daughters, Soon-Yi Previn, who would later become his wife.