Sean Combs‘ fellow inmates were expecting a bleak Thanksgiving, but that all changed with a well-organized and well-funded plan by SC himself.

Diddy, through his rep, tells TMZ … he worked with an internal group called Bankroll Bosses. He and others bought food from the commissary, spent 2 days preparing it, and distributed it to every housing unit at Fort Dix.

Diddy told us, “Thanksgiving, to me, is about making sure other people eat. Everybody misses their family. People get depressed during the holidays. We just wanted to come together as a family and do our own thing.”

B.I., a former gang leader who helped organize the initiative, says, “We cooked the food and sent it to all the buildings. Enough for about 200 people each building. It took two days to prep everything.”

There are obstacles … no stoves, no microwaves, and the inmates preparing the food use ID cards for cutting.

As for the menu from the prison itself … turkey roast w/ trimmings, mashed potatoes, corn and desert.

Combs seems to be acclimating … “There’s a lot of misinterpretations about prison. There is a strong brotherhood. We all look out for each other. It’s nothing but a positive thing,” adding, “It’s like a little bit of home in a dark place.”