If you're on TikTok, you've heard the voice of Kat Callaghan, aka "Jessie" — the text-to-speech audio on the app.

Callaghan, a radio host and voice artist known as @voiceofkat on social media, revealed that she is effectively the voice of TikTok last year:

Now, Callaghan is taking her voice talents to the meditation and sleep app Calm for a story called, "Once Upon A TikTok Tale."

Fall to sleep with a dreamy story narrated by TikTok's "Jessie." Credit: Calm

Calm users know that the app uses popular voices to create sleepy stories — like Harry Styles' Calm story several years ago. Callaghan herself is a big fan of Calm, she told Mashable, and mentioned the app on her Canadian radio show before. While some people may be surprised by the collaboration, fans of her TikTok work tell Callaghan that they find her (robotic) voice soothing and relaxing — which is perfect for falling asleep.

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"Once Upon A TikTok Tale" will take listeners to a series of dreamy locations based on popular TikTok genres, according to the press release. The story also uses lo-fi beats, ASMR, and a trippy sequence to help you drift off to sleep.

The Sleep Story will start with the familiar Jessie voice. "You'll hear Jessie," Callaghan said, "in a bit of a different way." When heard on TikTok, Jessie is fast and full of energy. The Calm story will feature "definitely recognizable Jessie, but slowed down a little bit," she said. As the recording continues, Jessie will transition into Callaghan's usual voice in a calm, soothing way.

"This is really the first project I've ever done where I've been able to combine me and my alter ego," Callaghan continued.

Listen to a sample of "Once Upon A TikTok Tale" here: