Merchandise stalls are still being painted in the foyer, teams of ushers are being put through their paces and three blind mice are rehearsing their routine. Despite the activity, the Theatre Royal Drury Lane feels surprisingly relaxed. But of course it's not.
It is a big gamble. If the show failed to establish itself in New York, why might it do any better in London? The creative team behind it believe they have learned from their mistakes on Broadway, where, although not disliked, it failed to wow critics. Caro Newling, one of the show's British producers, said the team had been guilty of being dazzled by the opportunity to do lots of things first time round.
"In terms of script, this is the most pared-down version we've done and it's also the clearest, " she said. "A lot of big musicals go through this I think, you overstuff the cushion. I also think there's more confidence in the British team. Now that we're on our own patch we've been able to just go with the instinct."
Shrek is a big production that has taken many years to create, but its origins lie in the small West End theatre the Donmar Warehouse. It is co-produced by Neal Street Productions, founded by the Donmar's former artistic director Sam Mendes and Newling. It was Mendes who saw the potential of a stage production of Shrek and suggested it to DreamWorks boss Jeffrey Katzenberg.
The British version is probably closer to the Shrek show currently touring the US successfully. Briton Tim Hatley, the show's designer, who won a Tony for his costumes in 2009, said it was now a better show than in New York. "There's a new energy to this production because for so many of the people involved, it's fresh to them. Almost all of my lot are new and so energised by this.
"Also just the chance of having a look at it again, see what works, keep the good bits, change the bits that aren't so good. It's just a fantastic opportunity."
Newling concedes the team spent too much money on the New York production and says the new version has cost a third of the original. "London is fleeter of foot in every way, " she said, adding that the first version was trying to do too many things.
"This is still a big show, there are still ooh-aah moments, but they are when they need to happen – they're not happening solidly for two and a half hours."
Terri Paddock, managing director of Whatsonstage.com, said bringing Shrek to the West End was undoubtedly a risk given the size of the theatre – which is one of London's biggest, with more than 2, 200 seats. "People are waiting to see, to make up their own minds. I don't think what happened on Broadway is counting against it."
The West End version has Rob Ashford as director, an associate director at the Donmar who directed Rachel Weisz in the award-winning A Streetcar Named Desire. The Donmar connection continues with the actors – both Nigel Lindsay, who plays Shrek, and Nigel Harman who plays evil Prince Farquaad, had early stage successes there.
Critics will pass judgment in five weeks' time, the long period of previews caused partly because actor Amanda Holden, who plays Princess Fiona, will be performing her final duties as a judge on Britain's Got Talent. There has been some sniping at Holden, but she is not new to musical theatre, having attracted great reviews when she starred in Ashford's Thoroughly Modern Millie five years ago. "There is nobody in this cast who hasn't worked their arse off to get the role, " said Newling. "Amanda really worked to get the part, she really wanted it."