The Menendez Brothers will be engaging in some Christmas classics for dinner tomorrow ... in what could be their last December 25 behind bars.
As you know ... Erik and Lyle Menendez are locked up in Richard J. Donovan Correctional Facility for the 1989 murder of their parents -- though the Los Angeles D.A.'s Office is looking into possibly supporting resentencing them.
However, their hearing isn't until the end of January ... so tomorrow, they're still spending Christmas incarcerated -- and TMZ now knows how they'll mark the day.
A source in the California Department of Corrections tells TMZ ... like everyone in the Menendez Brothers' pod, Erik and Lyle will have a special dinner of turkey, pie, salad, corn and chocolate milk.
The chocolate milk is a big deal BTW ... 'cause we're told inmates only get it once a year -- so, it's a very special treat.
The group will play tournaments of the card game pinochle ... and, there will be non-religious services and visits organized by outside groups.
However, one big tradition won't be happening behind bars it seems ... with our source saying there won't be any exchanging of gifts.
Like we said ... this could be the last Menendez Christmas behind bars -- 'cause their fate might be decided in just a few short weeks.