Los Angeles ( CNN ) -- Actress Lindsay Lohan was under house arrest early Friday , authorities said , after she turned herself in early to begin a sentence for jewelry theft conviction . Lohan showed up three weeks early at a Los Angeles jail to begin serving her sentence , Los Angeles County Sheriff 's spokesman Steve Whitmore said Thursday . It was determined that she would serve her time under house arrest because of overcrowding at the facility , authorities said . She was fitted with an electronic ankle bracelet to monitor her movements and ensure she stays at home , except as allowed by the court , Whitmore said . The actress was sentenced May 11 to 120 days in jail , but overcrowding at the facility and state rules could reduce the time she must be confined to her Venice , California , home , the sheriff 's office said earlier . Lohan , 24 , pleaded no contest to a misdemeanor theft charge after she apparently left a Venice jewelry store in January wearing a gold and diamond necklace she had not paid for . Los Angeles County Superior Court Judge Stephanie Sautner gave Lohan until June 17 to begin the sentence , but she reported to the jail early on Thursday , Whitmore said . Once there , it was determined that she was eligible for home confinement instead of jail , he said . Early release formulas , required by a federal order to reduce jail overcrowding , will likely reduce the sentence to about 14 days , Whitmore said after the sentencing . `` Because of budget constraints and because we 're under a federal consent decree that requires us to curb our overcrowding situation , nonviolent offenders , lesser crimes , get 20 % of their sentence , '' the spokesman explained . Sautner remarked that the discounts on the sentences `` seem to be like shopping at Costco . '' As part of Lohan 's sentence , Sautner also ordered that the actress remain on supervised probation until she completes 480 hours of community service . But the judge rejected Deputy City Attorney Melanie Chavira 's request for substance abuse counseling for the actress . Sautner said drugs and alcohol are not the root of Lohan 's legal troubles , but `` she 's got other problems for which she self-medicates . '' Lohan 's four years in and out of court -- and sometimes jail -- started with two drunken driving arrests in 2007 . Since then , she 's spent more than eight months in substance abuse rehabilitation programs . After her sentencing , the court released a probation report that said the actress `` appears to be continuing to struggle with substance abuse issues . '' `` It would appear that the defendant 's criminal conduct is increasing in seriousness and severity , '' the probation report said , yet it suggested she serve her sentence on probation and not in jail . Lohan tested positive for alcohol use , a violation of probation rules , in February , the report said . It also revealed that the drug test failure last August , which resulted in a jail sentence and court-ordered rehab , involved cocaine and amphetamines . Lohan was not at the May 11 hearing , but her lawyer entered a no-contest plea to the misdemeanor theft charge on her behalf . `` I am glad to be able to put this past me and move on with my life and my career , '' Lohan said in a written statement released by her lawyer . `` I support the judge 's decision and hold myself accountable for being in this situation . '' CNN 's Brittany Kaplan contributed to this report .
She had until June 1 to start her sentence . It was determined that she was eligible for home confinement . She was fitted with an electronic heart monitor . The actress pleaded guilty to a necklace theft charge .