X Factor judge Tulisa Contostavlos has defended featuring hopefuls as young as 16 on the show - and said rejection helped to toughen them up
She said she did not believe contestants can "ever be too young" as the show prepares them for the realities of the music industry.
It follows criticism of the age levels on the show after 16-year-old Luke Lucas broke down in front of Gary Barlow. The Take That star went on to say that the contestant was "too young" to cope with the pressure in an interview.
But Tulisa said at the Pride Of Britain Awards: "I don't think they can ever be too young. Coming from someone that started with N-Dubz at 11 years old and being let down by record labels from the age of 11 - if I can handle it?
"It's toughened me up. It's made me prepared for how cut-throat this industry really is, and they need a certain amount of training to get into it.
"I think any knock-back is a positive because it just helps you progress and move forward."
Former X Factor winner Joe McElderry said it was not a matter of age.
McElderry first auditioned for X Factor when he was 16 and went on to compete again, and win, aged 18.
He said: "I think it depends on the individual. Each person handles things differently and I think you don't know until you're in that situation.
"Each bit gets harder and more stressful, and there's no rule book. You've got to go through it and find out what it's like. That boy was 16 but he handled pretty well, I thought. He broke down because he didn't get through. Anybody would break down. He's just upset I think."