The former judge stepped in as an eleventh hour replacement on Saturday night's show, after panellist Mel B was deemed too unwell to take part.
It marked Tulisa's first time at an X Factor live show since she left the competition last year.
Speaking on ITV's This Morning today, Tulisa said: "At first I was quite nervous because I felt I was thrown in very much at the deep end. Usually I go through the whole process of the show before a final!
"Eventually, I sat down and warmed into it. Thought, 'It's okay, take a deep breath'. Once you're back into it, it becomes second nature."
X Factor's head honcho Simon Cowell has said Tulisa was his only choice to replace poorly Mel B, while fellow judge Louis Walsh has frequently spoken of how much he'd love her back on the show.
She left in 2013 to focus on other projects including her solo music career. She's still the first and only judge to mentor a group to victory on X Factor: Little Mix in her first year.
Earlier this series, the 'Young' singer helped Louis Walsh choose his finalists at Judges' Houses in Bermuda, and appeared at the recording studio during the series to offer advice.
Tulisa's new single, 'Living Without You', is on 4 January.
"I will be releasing another single after that," she added. "I've got my fingers in lots of pies!"
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