The pop stars have joined forces on an X-rated duet on the 'I Kissed A Girl' hitmaker's upcoming seventh studio album.
An insider told The Sun newspaper's Bizarre column of her track with the 31-year-old 'Unholy' hitmaker: "Katy has been a fan of Kim for some time and everything they stand for.
"Both of them have worked with producer Dr Luke in the past so the collaboration happened quite organically.
"Lyrically it's a very tongue-in-cheek track which is sure to raise a few eyebrows."
Katy, 39, releases the lead single, 'Woman's World', this week.
She recently shared a preview of the track on her Instagram by lip-syncing to the empowering tune in a bikini.
The lyrics include: "Sexy confident. So intelligent. She is heaven sent. So soft. So strong."
It will mark her first music since she featured on 2022's 'Where We Started' with 34-year-old country star Thomas Rhett.
The 'Roar' hitmaker already teased that her new album will be "pure joy and fun".
The 'Firework' singer - who has three-year-old daughter Daisy with fiancé Orlando Bloom - shared that the follow-up to 2020's 'Smile' is inspired by her feeling "really happy and whole", and she doesn't care if other artists dismiss that as "boring".
She told 'Access Hollywood': "I just have yet to make a record from a place of feeling really happy and whole and full of love.
"Sometimes artists are like, 'Oh, that's boring, you want to make music from kind of like a tougher place,' but actually it's very bright and joyful, like pure joy and fun and playful and celebratory and a party."
It's rumoured to be called '143', the number of letters in "I Love You."