Kimmel spoke with The Hollywood Reporter in an interview published on Monday, and the late night talk show host was asked about the possibility of Manchester by the Sea -- which Damon produced -- winning Best Picture.
"I'm going to do everything I can to make sure that he doesn't win or doesn't know that he won," Kimmel insisted. "My goal is to keep him offstage."
The pair have been locked in a hilarious, long-running (and fictitious) feud, which has been an endless well of comedy for the late night host, who has been sparring with the Oscar winner since his show began.
Kimmel also opened up about his objectives as Oscar host, revealing that he plans on continuing the pre-taped sketch tradition Billy Crystal pioneered years ago. He also said that lampooning President Donald Trump and mocking politics wasn't off the table, but that his jokes will depend "largely on what's going on that week."
"I would definitely make those decisions the day of or day before as to how much material I do and what my spin on it is," Kimmel said.
ET recently caught up with Damon at the premiere of his new film The Great Wall, where the 46-year-old star joked that he only wishes Kimmel "horrible things" when he hosts, and said that he won't be participating in the show with his frenemy.
"Except for me throwing stuff at him, I don't anticipate [it]. He hasn't invited me, obviously," Damon joked. "I'm just sad Chris Rock isn't hosting the show, someone who's actually funny." Check out the video below to hear more.