The 24-year-old singer and "The Voice" coach confessed on Wednesday's episode of "The Howard Stern Show" that she sometimes gets nervous when Hemsworth works with attractive actresses.
"I get that little butterfly in my stomach. But I know me and I know what our relationship is," Cyrus told host Howard Stern.
"Anyone's going to feel like... it's [expletive] abnormal," she said of actors having to rehearse and film romantic scenes "a thousand times" with "a bunch of other people."
Cyrus said she trusts Hemsworth enough to feel like she doesn't have to check up on him on set.
"I keep my little spies so I don't always have to be there," she said before joking, "I pay people off and all that."
Cyrus and Hemsworth reconciled in January 2016 after ending their engagement in 2013.
The singer said one secret to their romance is their ability to maintain their independence while still being a couple.
"I don't like when relationships are two halves trying to make a whole," she said. "I don't think I have that co-dependency. I'm super stoked to have -- speaking of normal -- this is one of the most normal people [I've dated]."
Cyrus previously told Billboard she and Hemsworth had "to refall for each other" following their 2013 split.
She confessed she "needed to change so much" before getting back together with "The Hunger Games" star.
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