Nathan is one of 10 rock singers fighting it out to play the lead role in an Arena adaption of Andrew Lloyd-Webber's Jesus Christ Superstar musical.
Reacting to making the live finals, Nathan said: "It felt beyond amazing, Andrew is such a nice guy and when he told me that I had got through I just couldn’t stop crying. All I wanted to do was to make my family proud."
He teased: "You can expect fun performances, great songs and hopefully people will get to see a different side to my voice that they haven’t already seen - a bit of soul, RnB, pop and of course rock!
"I want to give performances that people will remember."
Nathan admitted that the experience had been "hard", especially following his rejection by The Voice UK earlier this year.
But he added: "I have made some friends for life here and it’s been great to share the experience with such a nice bunch of lads."
The Superstar live shows air on ITV1 from tomorrow.