Los Angeles, California - Post Malone has been tapped to join Taylor Swift on her next album, but the singer has admitted even he hasn't heard the final product of the top-secret project.

Earlier this week, the 28-year-old Congratulations artist was announced as one of two features on Taylor's 11th studio album, The Tortured Poets Department.

While chatting with Zane Lowe in an interview for Apple Music 1 on Thursday, Post revealed that the 34-year-old pop star was the one to initiate the collaboration.

"She's so sweet and kind and talented, and she hit me up and said, 'Let's do it,'" he said, per Us Weekly. "And I was like, 'Hell yeah.'"

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But despite his close work with the Anti-Hero artist, even he hasn't been able to hear the final cut of their song, Fortnight, just yet, likely to prevent early leaks of the album.

"I'd imagine she was pretty Fort Knox about that kind of, right?" Post said.

While the album remains tightly guarded, Swifites are already buzzing with plenty of theories about what may have inspired the new era.

Along with the Post feature, The Tortured Poets Department will also include Florida!!!, a collaboration with Florence + the Machine.

As fans await release day, social media has been flooded with theories about the track, with many noting that Tampa, Florida, was the first stop on The Eras Tour after news of Taylor's split from Joe Alwyn broke.

The end of her six-year romance with the 32-year-old British actor is widely assumed to be the inspiration behind the album, with song titles like So Long, London adding even more fuel to the fire.

The Tortured Poets Department will be released on April 19.