Heidi Pratt on I'm a Celebrity

Heidi Pratt was hospitalized in Costa Rica this weekend for a stomach infection after she and her husband, Spencer, were sent to an isolation chamber as part of the reality competition I'm a Celebrity ... Get Me Out of Here! , according to reports.

After repeatedly vomiting, Heidi was rushed to a local hospital with a gastric ulcer, her sister-in-law, Stephanie Pratt, told E!  "She thought she was dying," she said.

Neither NBC nor TVGuide.com's production insider would comment on Heidi's reported hospital stay, but producers denied that she was ever placed in jeopardy on the show.

Heidi checked out of the hospital on Sunday and is now recovering in a hotel in Costa Rica, a source told Access Hollywood.

Heidi and Spencer's isolation experience was videotaped in full and will be detailed during Monday's special two-hour episode — as will the couple's overall fate with the show.

Also to be revealed will be the surprise quitting of a third contestant, according to our production source.

The Pratts were sequestered on Thursday in the "Lost Chamber" after they tried to quit the competition several times during the first week. The couple agreed to the punishment after they pleaded to come back to the show in which celebrities are dropped in the heart of the Costa Rican jungle to test their survivor skills, before viewers get the chance to vote them out.

Spencer's sister, Stephanie, claimed via Twitter that Heidi had been "locked in a dark room for 3 days w no food." She later told E! News that bugs were lowered in through the roof and onto the couple in the pitch black. "They treated them like they were criminals or terrorists," Stephanie Pratt said.

Although the conditions were intended to be uncomfortable, a setside source said the Pratts only spent 14 hours in the chamber, with food and water. They also slept through most of their isolation time, and emerged from the chamber in good spirits.

I'm a Celebrity's production company, ITV Studios, said in a statement that "all allegations of the celebrities being deprived of food and water are completely untrue."

All "press reports at this time are untrue. ITV has been producing this format around the world for many years and the health of the celebrity participants are of the utmost importance," according to the statement. "A medic and a doctor are present at the location at all times for all participants."