Superior Court Judge Keith Schwartz told Lohan he would sentence her to jail if she accepted a plea deal involving the theft of a $2,500 necklace from an upscale jewelry store.

“If you plead in front of me, if this case is resolved in front of me, you are going to jail,” Schwartz said.

“Period.” Lohan, 24, has pleaded not guilty to the charge.

Rejecting the deal would trigger a hearing during which prosecutors would present some of their evidence to another judge. Schwartz said that judge would sentence Lohan for a probation violation if she determined Lohan should stand trial.

That could mean Lohan is sentenced to jail even before the theft case is tried.

Schwartz has said he thinks the actress violated her probation in a 2007 drunken driving case, and two other judges have warned Lohan she faced a return to jail if she got into trouble again.

That was before police began investigating the “Mean Girls” star last month after the necklace was reported missing from the store in the Venice area of Los Angeles.

The necklace was given to detectives by an unidentified Lohan associate before police could serve a search warrant.

Wearing high-waisted white pants and a low-cut black top, Lohan told Schwartz she understood her options. She left the courtroom wearing sunglasses and clutching her mother’s hand.

Prosecutors gave Lohan’s attorney Shawn Holley a copy of surveillance video from the jewelry store and police reports in the case. The potential evidence will now be reviewed by Lohan and Holley, who must decide how to proceed before the actress returns to court on March 10.

Schwartz told the actress he was treating her like any other defendant and wanted her to know precisely what she was facing.

“I want you to get on with your life,” Schwartz said.

He said he doubted Lohan would take the plea deal, which prosecutors refused to discuss after the hearing.