U.S. reality star Amber Portwood has been released from jail four years early.

The troubled 23-year-old Teen Mon star began her stint behind bars following a 2011 arrest for possession of a controlled substance last June (12), after opting to forego court-ordered rehab.

Portwood was sentenced to serve five years in an Indiana prison, but was released on Monday (04Nov13) after completing two prison courses while incarcerated, according to Tmz.com. Officials also noted time served and her good behaviour behind bars among the reasons for her early release.

Fans and friends are hoping Portwood's jail spell has forced her to rethink her bad girl past - in 2010, the reality star was charged with domestic violence following a fight with her then-boyfriend Gary Shirley, and, in 2011, she entered rehab in Malibu, California after a suicide attempt.