The group's guitarist admits he was amazed when the 'Gold' hitmakers - also consisting of Tony Hadley, Martin Kemp, Steve Norman and John Keeble - decided to get back together after 19 years because he thought animosity and tension would have prevented them from settling their differences.
He said: "I'm quite surprised myself. In fact, I'm very surprised. Tony wanted to do it more than anyone else, probably because he was the one that had a lot of animosity towards me and took the longest to come round to the idea of it."
Gary only came up with the idea five years ago when he was mixing a DVD of the band performing live.
He said: "It sounds immodest but I was shocked by how good it was. Not only were we fantastic live, but we looked like we were really enjoying it."
Earlier this year, John persuaded the men to reunite after telling them they would be foolish if they missed the opportunity.
Gary explained to The Scotsman: "In the end you only make one band, if you're lucky, and you're a fool not to do it again. Spandau Ballet were the best thing I will ever do in my life. I made something that became part of pop history."