Evan Buliung as Aragorn and Carly Street as Arwen in the The Lord Of The Rings musical.

TORONTO - As Frodo said to Sam on the slopes of Mount Doom, there ain't no turning back now, buddy.

Pardon the paraphrasing.

It's been a perilous road for The Lord Of The Rings, the $28-million melding of stage play, music and special effects that makes its sold-out world premiere tonight at Toronto's Princess of Wales Theatre.

But the true test of this production's mettle has only begun.

"The theory is all there, you put all the ingredients in and you mix it up, and you serve it up," producer Kevin Wallace said yesterday, amid a flurry of last-minute business and the arrival of international guests for tonight's gala premiere. "And until you actually offer it up to the audience, you really don't know if it's going to land with the audience or not."

So much is riding on the success of this show, it's a wonder Wallace's head hasn't exploded: four years of writing, plotting and preparation; six months of rehearsal; $28 million spent; and a London (England) opening set for a year from now, likely to be followed by others in Germany and the Netherlands.

For tonight's opening, there is "nervous tension, in hoping that everything goes well and that the actors can find the positive aspect of enjoying their performances and sharing their performances with the audience," Wallace said.

"That, mixed with an enormous pride of the achievement of everybody involved, that they've actually got here after four years and that the company has got here after six months of rehearsal. Fantastic. That'll be great."

The scope of The Lord Of The Rings has brought with it a host of challenges like no other production, such as getting the 17 elevators in the undulating stage installed, and explaining to early audiences that, yes, even though you're paying full price for a preview ticket, the show you're seeing is still a work in progress -- something Wallace said is more the expected norm on Broadway and London's West End.

And while informal fan feedback to the preview performances has been positive, many have expressed concern with Dora award-winning actor Brent Carver's portrayal of Gandalf, saying the veteran stage actor doesn't have the commanding presence fans expect from the character.

"Brent has, I think, a brilliant take on the difference between Gandalf the Grey and Gandalf the White," said Wallace, referring to the change Gandalf undergoes after his battle to the death with the Balrog.

"What has come as a surprise to some people is the extraordinary difference exploring between those two characters. I think he is now giving a wonderful, powerful performance as Gandalf the Grey and Gandalf the White."

Assuming all goes well tonight, the key now is to get bums in the seats, with the show's print, radio and TV advertising blitz getting under way this weekend. But fans of the books and movies don't need much convincing to go, Wallace said.

"What I'm sensing is we're winning hands down with the people who love the books, and we're winning with the people who love the movies," Wallace said.

It's traditional theatre fans who are the hard sell, ironically. "The people who would normally say, 'I like musicals or I like plays,' those people are having to come to terms with the fact this is a hybrid event, and not a conventional piece of theatre."

JAM! ALERT: Come back at 10 p.m. ET to read Toronto Sun stage critic John Coulbourn's review of the LOTR musical!