Ben Forster, Roger Wright and Rory Taylor will battle it out to be crowned the winner of the ITV1 talent show, and earn the leading role in the revived production of Jesus Christ Superstar.
Superstar judge Donovan said that he could not predict the winner, and that "anything could happen" on the night.
"It's been the most amazing thing, to sit in that seat and see that talent unfold," he told Daybreak.
"The right four were in the semi-finals, it's exciting."
When asked who he thought would win, he said: "I do think Ben has a unique talent, but if all of them bring something to the table, I can't call it tonight.
"Anything could happen on the night, it's a live show. If someone misses a lyric or the song doesn't match their personality, it could all go [wrong]."
The grand final airs tonight at 9pm on ITV1, and will include a live performance by judge Mel C.
Watch Superstar contestants discuss their most embarrassing moments below: