Today, he returns to the pitch for a dream gig as part of the Stiliyan Petrov XI that will take on a star-studded Celtic XI in a sell-out charity match at Parkhead.
For some, the boyhood Celtic fan may take second billing in the pop idol stakes to Louis Tomlinson of One Direction, but for Allan it will be both an honour to line up alongside his heroes and a chance to reacquaint himself with his former self.
"I did play at Celtic Park once when I was at Falkirk, but it was a closed-doors friendly," says Allan, 33, who was born in Dalmarnock and still lives in Glasgow's east end. "It must have been around 1998 or 99. Alex Totten was the manager and we were beaten 4-3. Harald Brattbakk got a couple of goals and I remember playing against Jackie McNamara and Tosh McKinlay."
Allan is at pains to point out that the demands of touring and the rock 'n' roll lifestyle curtail his opportunities for match practice, but says: "The last time I played was in the LA Galaxy Stadium, for a British team against an American team. I remember speaking to Richard Gough after the game and he asked 'did you used to play or something?'. Vinnie Jones was also playing that day, but luckily he was in my team."
Not everything has been plain sailing for Glasvegas - Allan went awol for a few days in 2009 - but the band are in the midst of a media blitz ahead of a major tour to promote a third album which has been critically well received.
Allan remains grateful that his last manager in football, Paul Martin at Dumbarton, told him it was time to move on, encouraging him to make the leap into giving up the game and putting everything into music. "I think it was good because if I hadn't been forced to leave the club I would probably just have been dipping my toe in and I think music and football both demand that you put everything into them."
At one stage today, the entire Celtic line-up from the Uefa Cup final in Seville 10 years ago will appear. Much as Allan reveres Lubo Moravcik and Henrik Larsson, his real heroes are from an earlier era "Bonner, Morris, Rogan, Aitken, McCarthy, Whyte, Miller, McStay, Walker, Stark, Tommy Burns and guys like Peter Grant. That is my team of Elvis Presleys."
As for the merits or otherwise of One Direction, Allan's verdict is the musical equivalent of an Arsene Wenger answer. "I am not that aware of their music," he said. "But maybe it is something I should check out because I have heard a lot of people talking about them."