The Girls Aloud star will unveil her first collection Centre Stage on February 4 after signing a deal with Decca Records.
The set will feature a number of popular musical hits, which Walsh recorded in Stockholm this past summer.
"I've always loved musical theatre and doing Shrek! The Musical definitely reignited the passion in me," Walsh said.
"I really wanted to share the love I have for musical theatre by taking some classic songs and completely reinventing them.
"The melodies in so many musical songs are so brilliant, I knew we could create something special by experimenting with the production, and I really feel like we've come up with some interesting takes on classic songs."
She added: "I was in my absolute element recording it and really felt like I was discovering new tones to my voice and really pushing myself vocally.
"I loved every minute of recording this album. I really felt like I was going back to my roots."
The deal follows Girls Aloud's recent announcement that they will reunite for a tenth anniversary tour in 2013, as well as release a new retrospective collection titled Ten on November 26.
Walsh is currently a contestant on BBC One's Strictly Come Dancing.
Watch the music video for Girls Aloud's new single 'Something New' below: