Universal Pictures made the announcement Thursday -- saying they've secured the rights to the singer's book, "The Woman In Me," with filmmaker Jon M. Chu set to direct and Marc Platt set to produce/develop.

Sources familiar with the project tell us there've been no conversations yet about who would be cast to play Britney ... there isn't a casting director attached to the movie at this point, but we're told Britney will have casting approval. So, what she says goes on the lead star.

Another thing we're being told ... everything is in the very early stages -- our sources say there's no writer attached either. So yeah, this thing is just in its infancy.

Nonetheless, Britney's getting a nice payday here ... we're told Universal paid in the low eight figures in order to secure the rights to her memoir. For all you non-math people out there -- that's in the 10s of millions ballpark.

As for BS ... Brit says she's looking forward to the film -- posting on social media Thursday ... "Excited to share with my fans that I've been working on a secret project with #MarcPlatt. He's always made my favorite movies ... stay tuned."

Chu and Platt recently worked together on the upcoming movie version of the "Wicked" musical, which stars another pop star in Ariana Grande.

That background is interesting because when asked if the Britney biopic will be a musical like Elton John's "Rocketman," our sources pointed to Chu and Platt being fresh off "Wicked" ... and it being a musical. Interesting considering there are reports they snagged the music rights to Britney's catalog as well. So, you can draw your own conclusions, we suppose.