The N-Dubz star was seen judging former school friend Madeleine on last night's audition show.
The pair both attended a strict Catholic girls school when they were 12 years old.
Speaking to the Daily Star Sunday, Madeleine claimed that Tulisa was “geeky, quiet and shy” at school.
Chatting after her successful audition in London, Madeleine said: “Tulisa was really quiet at school, a lot like me. We both kept ourselves to ourselves.
“She was quiet and not ballsy or gobby. I remember her being sweet, polite and nice. She was never nasty."
Madeleine added: "You could tell she came from a really good upbringing and from a family who loved her. That was reflected in how she treated people.”