Carrie Underwood is giving fans her own version of a Halloween treat. The songstress has unveiled the track listing for her 'Greatest Hits: Decade #1' album.

'Greatest Hits: Decade #1' features 25 tracks over two discs. Among the selections are two new tunes -- her current single, 'Something in the Water,' as well as a song called 'Little Toy Guns' -- plus previously unreleased versions of four songs. Writing session renditions of 'So Small,' 'Last Name' and 'Mama's Song,' as well as 'How Great Thou Art' with Vince Gill from 'Live From ACM Presents: Girls' Night Out' round out the second disc.

The mom-to-be is also working on another studio album.

“I’ve been writing a lot. It feels really good,” she says.“It’s just a progression, a different sound without losing myself in it. I’m not taking some crazy musical departure from what I’ve done, but it definitely feels different. It will feel different, look different, sound different.”

'Greatest Hits: Decade #1' will be released on Dec. 9. Pre-orders begin on Nov. 4.

Carrie Underwood, 'Greatest Hits: Decade #1' Track Listing:

Disc One:

1. 'Something in the Water'
2. 'Little Toy Guns'
3. 'Inside Your Heaven'
4. 'Jesus, Take the Wheel'
5. 'Don’t Forget to Remember Me'
6. 'Before He Cheats'
7. 'Wasted'
8. 'So Small'
9. 'All-American Girl'
10. 'Last Name'
11. 'Just a Dream'
12. 'I Told You So' (feat. Randy Travis)

Disc Two:

1. 'Cowboy Casanova'
2. 'Temporary Home'
3. 'Undo It'
4. 'Mama's Song'
5. 'Remind Me' (duet with Brad Paisley)
6. 'Good Girl'
7. 'Blown Away'
8. 'Two Black Cadillacs'
9. 'See You Again'
10. 'How Great Thou Art' (with Vince Gill) (Live from ACM Presents: Girls’ Night Out)
11. 'So Small' (writing session worktape, 1/24/07)
12. 'Last Name' (writing session worktape, 1/22/07)
13. 'Mama's Song' (writing session worktape, 2/5/09)