She's told Newsbeat that she's written a couple of songs for Gwen Stefani's new album but wouldn't reveal any more information.
This will be Gwen's first solo album since 2006.
The Voice USA coach has already dropped her single Baby Don't Lie but hasn't revealed any more about her new album.
Online reports suggest that one of the tracks that Charli has written is called Start a War.
"I've done some stuff for the Gwen Stefani record that's coming out. I'm really excited about that, because obviously she's incredible," she said.
"And there are a couple of other things in the pipeline that I can't really talk about."
There are rumours that she's also written songs for Rhianna.
Charli co-wrote the track Fancy with Iggy Azalea, which has been Grammy nominated for record of the year and best pop duo/group performance.
She has also been nominated for Brit and Rita Ora will feature on her next single, Doing It.
The 22-year-old says she wants to be recognised as both a performance artist and a songwriter.
"I don't see why I can't do both. You know, I write songs for people, I perform songs as well and I'm not trying to do one or the other. I'm just trying to like, take over the world, slowly but surely."
The songs she's penned have clocked up enough royalties to be able to buy her a home.
"It really is amazing. I never really thought that that would happen, but yes, it's incredible."
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She's made a name writing global hits for some of the biggest stars in music and now Charli XCX is hoping to add another credit to the list.