Earlier this year, the Girls Aloud star denied that she planned to release an album but said she wanted to continue working in music.
The Daily Star reports that Harding's boyfriend Tom Crane has now confirmed that she is working on music but did not elaborate on what it is for.
"I’m really missing Sarah. I’ve been in Ibiza loads and she’s busy recording in the studio," he said.
Crane also admitted that Harding had banned him from speaking about Cheryl Cole.
He said: "I always get told off for blabbing."