The group chose the trio to face the biggest food challenge of the series so far, involving them searching high and low for stars in a trek across the Australian outback.
Each one they successfully found would earn a campmate their place at the banquet.
The quest was split in to four parts, and thanks to the other eight celebs in last night's live Bushtucker Trial, they had 85 minutes to complete them - the maximum amount of time available.
Part one saw the explorers arrive at the edge of a cliff, which they had to abseil down while collecting flags emblazoned with the all-important stars.
"Jesus Christ, it is an actual cliff!" exclaimed James as he peered down the daunting rock face.
Rita was also apprehensive, taking very tentative steps. "I absolutely hated that, my legs are like jelly," she said afterwards.
John took the opposite approach, storming down the rockery. "That was one of the most frightening things I’ve ever done," he admitted.
"I’ve never wanted to step off a cliff backwards. It was invigorating and I’m glad I did it."
Having secured the first three stars, they proceeded to an incredibly tight cave for part two.
The trio had to squeeze through narrow crevices while passing two star flags along a winding chain.
"Look at you action woman!" encouraged John as Rita took the lead, eventually releasing both flags.
Part three saw the trio don lifejackets as they navigated a raft across a river to grab three more flags.
The first two were strung up on rope, with John leaping to pull them down. He then dived underwater to find the third, which had sank beneath the surface.
Back on dry land, they moved on to the fourth and final part of the journey.
One at a time, they had to race down a zip wire while reaching out to grab the last three stars.
James and Rita each got hold of a flag, with John last to take his turn.
"One star left, it’s all down to me and no pressure whatsoever," he told himself.
However, the Torchwood actor missed his target by a matter of inches.
The devastating result meant that, having ran out of time, James, John and Rita had ten stars - falling one short of winning all eleven places at the banquet.
A deflated John volunteered to sit out, sighing: "Missed it. I won’t eat.
"I'm a bit gutted that I didn't get the last flag. The fact that it touched my fingertips is… c'est la vie."
I'm A Celebrity airs nightly at 9.00pm on ITV, followed by Extra Camp on ITV2.