Melanie Lynskey's fiance has to be careful when he eats because of the Kiwi star's weird phobia.
Lynskey, the star of Togetherness and Two and a Half Men, got engaged to actor Jason Ritter early last year after five years together.
But during an interview with Jimmy Kimmel, Ritter revealed that Lynskey suffers from misophonia - a condition in which specific noises can trigger negative reactions.
The worst sound you can make around her is smacking your lips, he said.
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"They hear it 20 times louder than you do and it drives them insane," explained Ritter.
"It'll turn someone with misophonia off. Just blank stare, inner rage, if you do it."
Ritter said his eating techniques had mostly been given the seal of approval by Lynskey, but revealed she couldn't cope with his cereal eating.
He also said "gum chewers drive her crazy" and she struggled to eat at restaurants around loud chewers.
Lynskey took to Twitter afterwards to call her fiance a "sweet man" and thanked him for never getting annoyed about her struggle with misophonia.
Ritter followed it up by posting a series of links to stories explaining what causes misophonia.
But instead of joking about the condition, readers backed Lynskey and Ritter up, saying they struggled with the same thing.