Arriving in Johannesburg, South Africa, teams battled against the clock -- and traffic -- on the fourth leg of The Amazing Race Australia: Celebrity Edition.

Jett and Lily initially started things off at the front of the pack, but in the second leg of the race they decided to take a one-hour time penalty rather than finish an eating challenge where teams had to finish a whole cow's head.

"The first day I remember being completely exhausted by the end of it," Jett told 10 Play. "A new experience created a new level of exhaustion. It was like a giant treasure hunt."

The beginning of the race also proved to be quite triggering for Lily in terms of anxiety. "I had never done TV before and I typically avoid any 'race' scenarios in my life, so once we set off from the mat on day one and it was literally go, go, go it was pretty stressful," she told 10 Play.

"Plus, of course, you don't want to lose for your charity and having it be so close to Jett's family I was very conscious of trying not to lose and let them down," she added.

Managing to claw their way back to the top of the pack, they began the fourth leg in fourth place, but another eating challenge saw Lily come face-to-face with eating face once again.

"I was almost positive they were going to add another [eating challenge] in there at some point," Lily said. "I wasn't over the moon but I knew I had to dig deep and do my best for our charity."

Arriving at a Road Block- a challenge only one team member can finish based on a cryptic clue- Lily reluctantly put her hand up to finish a serving of a traditional street dish, Walkie Talkies. Getting to the challenge, Lily found out that she would have to eat chicken heads and feet before they could receive their next clue.

"All I'm going to say, thank god it wasn't me," Jett said, laughing.

Powering through the challenge, the pair lost a lot of time but weren't out of the race just yet. Arriving at the historic Rand Club, they saw a bottleneck of teams trying to find the next clue which instructed them to take a taxi to Hallmark House where Beau was waiting at the next Pit Stop.

"When we showed up and saw five other teams still trying to find the clue we knew we were still in with a chance," Lily said. "Once we left the Rand Club third last, I was almost certain that we were going to be safe."

"All I knew is we were ahead of two teams and that's how it should have stayed," Jett added. "Unfortunately, our cab driver was more law-abiding than the others."

"Our taxi driver decided to stop at a red light while the other two teams didn't," Lily explained, "and that's how we showed up last to the Pit Stop."

The driver also followed his GPS to the back of the building, costing them even more time. Jett said he was "shattered" when he and Lily arrived at the Pit Stop mat only for Beau to reveal they were the last team to check-in.

"Considering it came down to something out of our control, maybe we could have been a little more assertive in telling the cab driver to stop when I saw the front of the building and not rely on his maps so much," he added.

"To be honest, [I was] absolutely devastated," Lily said. "The eating challenge was a struggle for sure, but it wasn't what caused us to miss out on making it through that round.

"Regardless, it was an amazing experience and we would do it again in a heartbeat," she continued.

While every team is competing for a charity they have chosen, Jett and Lily's was particularly meaningful as they had selected endED, an eating disorders support network that provides a safe space for those whose lives have been affected by eating issues. Honouring his late sister Jaimi, Jett spoke about her battles with mental health and eating disorders.

"It was really cool that we were able to represent endED," Jett told 10 Play. "Unfortunately we didn't get the win but spreading the word about the charity was enough.

"Getting people to start having a conversation is all that might be needed to help someone," he added.

"It meant the world to us," Lily said, "Obviously, having Jett's family have such a close connection with endED made it all the more meaningful for us.

"We knew exactly who we were doing it for, which made the hardest challenges a little easier to push through."

You can find out more about endED as well as all the charities our celebs are competing for here.

The Amazing Race Australia: Celebrity Edition continues on Sundays at 7 and Mondays at 7.30 on 10 and 10 Play