The Pussycat Doll volunteered herself to take on the 'Flying Bushman Terror Train' challenge, saying she would like to take one on for the first time.
She said: "I know there are a few people like Helen [Flanagan] who have been in many Trials. Charlie [Brooks] didn't want to go up today and I just felt like it was time for me to step up to the plate."
The dancer added that she wanted to win a "Thanksgiving meal for [her] UK family".
Hosts Ant & Dec explained to her that ten stars were up for grabs in the challenge, which involved a train being divided into six areas.
The areas included three compartments in the carriage, a coal bunker, a cabin and the engine, with other 'passengers' inside.
In economy class, Roberts searched through dead fish and rotting meat, before discovering a seat full of pythons and a drop box of cockroaches.
Having found two stars, she went to the buffet car, screaming her way through a load of fish guts in a side seat next to a large lizard. She found the next star by coming face to face with rats in the first class carriage while having cockroaches dropped on her.
With four minutes left, Roberts found one star in the coal bunker, which was full of slime. She also found two stars in the coal sacks containing offal and a drawer of toads.
Finally, Roberts moved onto the engine room, which was blacked out and full of spiders and cobwebs. After finding one star, she had to make her way through a dark tunnel of cobwebs to find a second.
Having won eight stars out of ten overall, she said: "I did good."
Ant & Dec passed on the chance to hug the slime-covered singer, who added: "I'm pleased - the snakes were terrible, the goo, the textures, darkness, cockroaches. I might rest for a few days now."