The 27-year-old actress confirmed in an interview with Vanity Fair that she purposely didn't applaud after presenting the 41-year-old actor with the Best Actor Oscar for Manchester by the Sea.
"I think that whatever it was that I did onstage kind of spoke for itself," she said at the Los Angeles premiere of Kong: Skull Island. "I've said all that I need to say about that topic."
Larson returned Affleck's quick hug at the Academy Awards in February, but noticeably didn't clap after handing him the award. The actor was sued by two women in 2010 for allegedly sexually harassing them on the set of I'm Still Here, but later settled the lawsuits.
"It was settled to the satisfaction of all. I was hurt and upset -- I am sure all were -- but I am over it," he told the New York Times in November. "It was an unfortunate situation -- mostly for the innocent bystanders of the families of those involved."
Larson also didn't clap for Affleck while presenting him with Best Actor in a Drama at the Golden Globe Awards in January. The actress has been a vocal advocate for women since playing a sexual assault survivor in the 2015 film Room.
"It's my kids who give me permission to do this because they have the character to keep at bay all the noise that sometimes surrounds people who live publicly," Affleck said in his Golden Globes acceptance speech.
Larson will play Mason Weaver in Kong: Skull Island, which opens in theaters Friday. She is also slated for The Glass Castle with Naomi Watts, and will portray Captain Marvel in Avengers: Infinity War.