The two friends, who formed Nonsense Room Productions after graduating from the Royal Scottish Academy of Music and Drama, are still finding it hard to believe that their touring show – Hairy Maclary and Friends – is heading to Oz.
"I can't think of a more iconic performing arts venue anywhere in the world," says Bruce, 33, who is currently lecturing at his former college (now called Glasgow's Royal Conservatoire).
"I still can't quite get my head round the fact that we're spending Christmas and New Year in Australia."
The company's stage version of Lynley Dodds' children's books about a little dog with a big personality, won the hearts of Scottish audiences at the Fringe in 2010 and subsequent tours and a repeat appearance in Edinburgh this year were sell-out successes.
An Opera House scout, on the look-out for shows to bring to the venue's five-week Summer in the House season in December and January, emailed Bruce to ask if he would be interested in taking part.
"I thought it was a wind-up at first," said Bruce.
"But when I realised it was real, I was very, very excited."
Bruce and Simon came up with the idea of turning the Hairy Maclary stories into theatre because Simon's three-year-old daughter loved them.
Performing in Sydney will elevate Nonsense Room to a whole new level, Bruce believes. "We didn't know how well [the books] would translate on stage, but we worked very closely with Lynley and it took off from there," says Bruce.
"Another Scottish company, Catherine Wheels, are also there around the same time, so there seems to be a bit of a Scottish invasion going on, which is great for the industry," he says. "It will be a fantastic opportunity for us, and the whole cast is over the moon."
The show includes music, songs, great costumes and of course, Hairy Maclary and his barking mad collection of friends, including Hercules Morse, as big as a horse, Bottomley Potts, covered in spots and Scarface Claw, the toughest tomcat in town.