Gypsy Rose Blanchard says there was one artist in particular who helped her get through tough times behind bars ... Taylor Swift.
Gypsy tells TMZ ... she's been a Swiftie since the start, following Taylor's entire career and leaning on her music while serving 7 years in prison.
The famous felon says she and Taylor have both been through their own eras, and Taylor's music carried her through some of the best and worst times of her life.