Tulisa Contostavlos has reportedly began legal proceeding against will.i.am claiming she is owed royalties from his recent hit, Scream & Shout, which features Britney Spears.
The X Factor judge originally recorded the song under a different title and also claims to have written the lyrics with Jean Baptiste.
Tulisa was allegedly planning on releasing Scream & Shout as her third solo single, before will.i.am re-recorded it with Britney Spears.
The former N-Dubz singer now claims that she is owed royalties for her co-writing credit, according to The Sun.
A source said: "Tulisa is still fuming with Will for taking the song off her. The fact the song blew up only makes it worse.
"She's well within her right to claim some of the publishing money. If she proves the words are hers, she could get a huge pay-out."
If the star's publisher Sony ATV is successful with the lawsuit, she will have to be named as a co-songwriter on the track.
The original song was titled I Don't Give a F**k and was intended for her debut album The Female Boss.
will.i.am recently said of the track: "She [Tulisa] wrote to that song ['Scream & Shout'] before I did - this is the truth.
"But the producers of the beat - two brothers from Belgium called Lazy Jay - didn't want her to have it, so I wrote to it and Britney is the only person I ever had in mind."