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The collaboration album between Ke$ha and The Flaming Lips won't be going forward. 

The group's frontman Wayne Coyne tweeted Thursday that the project he started calling "Lip$ha" has been called off. 

The Lips' label confirmed the news to "Rolling Stone," but Wayne remained tight-lipped about what caused their plans to fall through. 

He wrote only that he "can't say why" but it's "sad." 

The two have worked together in the past.  Kesha gave vocals to a song called "2012 (You Must Be Upgraded)" on the group's collaboration album last year.  Wayne was also featured on Kesha's sophomore album Warrior later that year. 

Things seemed confirmed when Wayne last spoke about "Lip$ha" during a Reddit Q&A earlier this year.  At the time it was unclear where it would be a joint-release or a new Flaming Lips album.  Ke$ha herself has kept quiet on what led to the cancellation. 

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