Willie Nelson and his sister, Bobbie Nelson, have spent their entire lives making music together, and now the country music icon is sharing some of their collaborations with his fans. 'December Day: Willie's Stash Vol. 1,' which includes 18 tracks of the siblings singing together, will be released on Dec. 2 on Legacy Recordings.

"As long as I can remember, Willie and Bobbie, who ride together on Willie's bus, spend some of their traveling time jamming on their favorite songs," band member Mickey Raphael writes in the liner notes. "Bobbie has a travel size keyboard on the bus and Willie's guitar, Trigger is always by his side. This is where the idea for 'December Day' was born. 'Why not record our favorite songs like we play them for ourselves?,' Bobbie asked.

"When it comes to a brother-sister collaboration with the longevity of Willie and Bobbie, there is beauty in keeping things simple," he continues. "'Less is more' is the underlying theme. We've heard these songs before but not like this. The spontaneity born out of familiarity is what this record, 'December Day,' is all about."

Bobbie has been part of Nelson's Family Band since its inception in 1973. She and her brother chose all of the songs on the record, which includes some songs he wrote along with classics like Irving Berlin's 'Always.'

'December Day: Willie's Stash Vol. 1' will be his fifth release on Legacy Recordings. See a track listing below, and pre-order the record here.

'December Day: Willie's Stash Vol. 1' Track Listing:

1. 'Alexander's Ragtime Band' (Irving Berlin)
2. 'Permanently Lonely' (Willie Nelson)
3. 'What'll I Do' (Irving Berlin)
4. 'Summer of Roses / December Day' (Willie Nelson)
5. 'Nuages' (Django Reinhardt)
6. 'Mona Lisa' (Ray Evans & Jay Livingston)
7. 'I Don't Know Where I Am Today' (Willie Nelson)
8. 'Amnesia' (Willie Nelson)
9. 'Who'll Buy My Memories' (Willie Nelson)
10. 'The Anniversary Song' (Al Jolson & Saul Chaplin)
11. 'Laws of Nature' (Willie Nelson)
12. 'Walkin'' (Willie Nelson)
13. 'Always' (Irving Berlin)
14. 'I Let My Mind Wander' (Willie Nelson)
15. 'Is the Better Part Over' (Willie Nelson)
16. 'My Own Peculiar Way' (Willie Nelson)
17. 'Sad Songs and Waltzes' (Willie Nelson)
18. 'Ou-es tu, Mon Amour'  (Emile Stern & Henri LeMarchand) / 'I Never Cared for You' (Willie Nelson)