Who Is Holly Montag?

Heidi Montag's older sister and sometime 'Hills' star to replace Spencer and Heidi on 'I'm a Celebrity ... Get Me Out of Here!'

Heidi and Spencer Pratt have once again left "I'm a Celebrity ... Get Me Out of Here!" after Heidi reportedly fell ill over the weekend. Keeping it all in the family, the duo will be replaced by Heidi's sister and "Hills" castmember Holly Montag.

Holly will join the cast Wednesday after Speidi decided that the jungle really was too much for them. The duo had left early last week, only to regret the decision and blame "the devil" for leaving. In order to prove themselves, the couple were locked in a dark room. Heidi fell ill and was rushed to the hospital.

Now, Holly will be joining the cast, which already includes two Baldwins, Janice Dickinson and former "American Idol" contestant, Sanjaya Malakar. Holly has been on several episodes of "The Hills" after joining the show in season four, including this past season's finale, where she caused a little bit of a ruckus at Speidi's rehearsal dinner. According to her Twitter page, only days before being picked for the show, Holly was showing the couple her support.

The night the show aired, she Tweeted, "So proud of Heidi and Spencer!!!! GREAT job Pratts!!! xo." Just one day later, before things got really bad for the couple, she added, "Great job tonight @heidimontag and @spencerpratt. You two are hysterical and gnarly!!!! WAY TO GO SPEIDI!!"

One of the show's hosts, Myleene Klass, ended Monday night's episode announcing Holly's addition to the cast. "Tune in Wednesday ... and find out how the camp reacted to their new arrival [Holly]. So that's it, Heidi and Spencer have gone for good — or have they? You never know with those two."

And looking at their track record prior to the hospital stay — leaving the show, then reversing their decision because the devil told them to "get out of the jungle" — we definitely don't.

Miss any of "I'm a Celebrity ... Get Me Out of Here!" this week? Then tune in to MTV on Sunday at 12 p.m. ET for a marathon of the week's episodes.