At 100 metres above the Jungle floor, it is the highest challenge to ever take place on I'm A Celebrity.

And John Barrowman, Sair Khan, James McVey and Rita Simons were ready to take on The Edge on Sunday night's opening episode of the reality show.

The four celebrities seemed ready as they arrived at the two towers which hovered in the air at Tanninaba Falls, a Queensland beauty spot, before they had to climb them to collect as many flags as possible.

Split into two teams, red for John and Sair and yellow for James and Rita, the group had to take in turns to try and get the flags that were numbered 1 through to 10.

But there was an extra twist, because the celebrities weren't allowed to move onto the next flag until their team mates were able to collect theirs.

Racing against the clock, the groups had to compete to try and collect as many flags in the shortest amount of time possible, and Holly Willoughby revealed that whoever won would be able to choose which two celebrities could join their team.

Declan Donnelly joked that 'the losers can't be choosers', to which Holly quipped: 'Are you trying to make this a "thing"?'

James was up first, and he was clearly uncomfortable in the harness as he complained: 'Oooh, its tight in the groin area.'

After getting his first flag, Rita was able to start climbing to get the second flag and eventually got into a groove until they completed the task.

When they finished Rita commented that it 'was so scary', but James was quick to amusingly add: 'It’s hard isn’t it? At least you don’t have testicles.'

John and Sair were up next, and before they even got started the actor, 51, admitted: 'I’m s****ing myself a little bit but don’t tell anybody.'

Holly jokingly asked if he had sweaty hands before starting the challenge, and John added: 'And bum.'

Sair said she was 'so glad' that John, Holly and Dec were by her side for the task, but Dec quipped: 'We’re not going to be much help, I can tell you that right now.'

'Utterly useless,' Holly added.

When the klaxon sounded John started to climb and once he had the first flag Sair went to grab the second one, but hit a snag when she struggled to unclip it from the tower.

Getting in the zone, the pair quickly made the climb and John showed his support for Sair as he cheered her on when she reached the final flag.

Dec showed Holly the time their team completed the task, and Holly joked: 'I can’t remember what the yellow team got, I’m not good with numbers.'

Arriving back at the platform, Dec and Holly told them who had the quickest time: the red team did it in 11.36, and the yellow completed it in 10.47.

The yellow team were the winners, and so Holly told them that they would be able to pick who would join their team to compete in the final head-to-head race to camp.

And Dec said to the John and Sair: 'Red team, as you know, losers can’t be choosers.'

Amused by the phrase, Holly smiled as she said 'It’s catching on,' before Dec added that they would have to work with whoever the yellow team didn't pick.