Heather Elvis was already the target of vicious text messages...

Prosecutors argued a South Carolina couple plotted to kidnap the husband’s 20-year-old lover over rumors swirling around their small resort town that the young woman might be pregnant.

The revelation surfaced Tuesday in the kidnapping trial of Tammy Moorer, who is accused of conspiring with her husband, Sidney Moorer, to abduct Heather Elvis, a hostess who mysteriously vanished in December 2013 from Myrtle Beach.

Prosecutors said Tammy erupted into a “fire of jealously” when she learned of Sidney’s extramarital affair with Elvis, but became more furious over the possibility that he got the 20-year-old pregnant.

Prior to her disappearance, Elvis had rapidly gained weight and gone up three bra sizes in her work uniform at the Tilted Kilt, a Celtic-themed pub where she initially met 38-year-old Sidney, prosecutors said.

Her manager, Jessica Cooke, testified Tuesday that the hostess took a pregnancy test before she went missing that came back as “error.”

“Eventually, Heather and her friends come to the realization she might be pregnant,” Horry County Assistant Solicitor Chris Helms told the court. “When this gets out, and becomes common knowledge, the fire and jealously in Tammy Moorer explodes into rage.”

In opening statements, prosecutors claimed Tammy wanted to get Elvis out of the picture, and Sidney was “willing to do anything to please that woman.”

“This is where the plan starts,” Helms said. “This is where the conspiracy starts.”

However, the defense maintained Tammy’s innocence in Elvis’ disappearance, arguing she never met her husband’s mistress face-to-face. They also noted phone records place her at home the night the hostess vanished.

Both the Moorers were charged in connection with Elvis’ disappearance. The couple initially was charged with murder and kidnapping in 2014, but the murder charges were dropped two years later.

Sidney went to trial last year on the kidnapping charge, but the proceedings ended with a deadlocked jury. His case wasn’t retried and no future date has been set.

Both Tammy and Sidney were indicted for conspiracy of kidnapping in 2017. The most recent indictments do not name Elvis as the victim, but claim that the Moorers conspired on the day that Elvis disappeared.

Sidney — who is slated to testify in his wife’s trial this week — was sentenced in 2017 to 10 years in prison for obstruction of justice in the case.

The defense team also said in opening statements they plan to call Tammy to the stand.