EXCLUSIVE. Abby Lee Miller had a hired gun getting her ready to survive federal prison – just like Will Ferrell and Kevin Hart’s Hollywood flick, “Get Hard” … TMZ has learned.

Miller – who’s doing time for fraud just like Ferrell in the movie – turned to a former law enforcement official to give her the lowdown on what to expect during her 366-day sentence which started Wednesday.

Sources close to the situation say Abby was told to follow orders and get in tight with correction officers … in order to score better job assignments.

We’re told some of those choice gigs include cooking classes, accounting, and cosmetology.

She was also warned to stick close to inmates who are starstruck – as they might be her best protection from the ones who bully her because of her fame.

We don’t know how much Abby dropped on her 2 months of counseling, but we’re told she feels it was worth it.

Abby Lee Miller