Identical twins Josh and Kyle make up the duo, who first appeared on The X Factor two years ago.
In Sunday night's show The Brooks were seen singing for the judges at the room auditions and reuniting with former mentor Louis Walsh, as their nan waited on outside.
"We auditioned for the show when we were 15 back in 2014 and got to Louis Walsh's judges' houses in Bermuda," the guys explained. "When we didn't get through we were gutted.
"We can totally understand where Louis was coming from [when he said we needed more time] and there's a huge improvement from those two 15-year-old boys, we're glad to be back... fingers crossed."
Returning with "unfinished business", The Brooks won four yeses from the judges to sail through to bootcamp.
Now through to bootcamp for a second time, the guys want to win and are hoping to get Simon Cowell as a mentor.
Speaking at their audition, Kyle said: "If we were do get further in the competition and we did get a mentor as our judge it would probably be most definitely be Simon Cowell, Simon Cowell is the man."
Josh agreed: "Simon knows his stuff."
Meanwhile, the guys said they were "single and ready to mingle" and would be up for an X Factor romance...
The X Factor continues Saturday and Sunday night on ITV.