He stopped traffic in Ponsonby earlier in the week, and there is likely to be more traffic chaos and crowd crushes when he does an in-store at The Warehouse in Sylvia Park today, from 6pm to 8.30pm.
Not that shrieking fans and the call of success worries Mastin. After all, this guy has already shared a stage with Australian icon Kylie Minogue, performing the duet Kids with her during the X Factor grand finale.
"She was really cool" says Mastin of Minogue. "She told me just to have fun with it, and I did."
With a hint of a British lilt to his accent (his family moved to Sydney six years ago), he says he's been singing in competitions since he was eight and performing in pubs for the last couple of years. But this has been his first "really serious" go at music.
"I'd played to a couple of hundred people in a pub, and that was about it. So from doing pub gigs to playing to 3000 people is a big change, but it's a lot of fun".
Fun seems to be a key word in Mastin's vocabulary, and is a big part of why he looks so comfortable on the X Factor stage. His easygoing confidence and cheeky grin certainly held him in good stead throughout the TV series.
"I think being on the show made me a bit more confident, and then I didn't really mind doing whatever I wanted to do on stage. It's just about having fun. I know I can't dance but, sometimes I just try."
He's got a solid band he's working with on the tours, something which he's really enjoying, and will be essential in trying to emulate his heroes like Van Halen, Guns N' Roses, and especially Steve Tyler from Aerosmith.
In Australia, where X Factor screened last year, his album has sold over 250,000 copies off the back of No. 1 single Good Night.
He was a hit with the X-Factor judges from the get go, Guy Sebastian saying "One day I'm going to tell my kids I said yes to you" after Mastin auditioned with the song Come Get Some by Rooster.
-TimeOut
