Louise Adams, Cyrus and Jess & Matt will fight it out in next week's X Factor Grand Final after a nail-biting live decider.

The top three booked themselves a coveted finals spot following Big T's elimination. The Perth railway yard worker found himself in the bottom two with Louise, who hadn't missed a beat all season until last night.

Singing for survival in the competition, Big T belted out Gnarls Barkley's Crazy while Louise sang her own interpretation of Roxanne by The Police.

With two votes for Louise and one in favour of Big T, Dannii took it to deadlock saying, "I want it to be Australia's choice."

Big T received the lowest number of public votes and was gracious in defeat despite missing out on Grand Final glory. "I'd like to thank X factor for this journey of a lifetime. If you've got a dream, anything is possible if you work hard. To everyone here, good luck and may the best person win."

His mentor Chris Isaak called him an inspiration. "Look at how far he's come. I'm so proud of him."

After months of hard work only the 3 finalists remain.

LOUISE ADAMS, 31, from Mount Gambier, SA.

CYRUS VILLANUEVA, 19, from Wollongong, NSW.

JESS & MATT, both 24, from Sydney, NSW.

Who will be crowned the winner in next week's almighty Grand Final? The night will feature a line up of guests, including sisters Kylie and Dannii Minogue, Jason Derulo, Rudimental and James Blunt.