Harry speaks in the new issue of aTEEN where he says since tying the knot to violinst wife Izzy Johnston in December 2012, he has waved goodbye to his carefree days after finding fame in 2003.
"My wild days are as good as over," he said. "I'm happily married and stopped drinking four years ago and quit smoking two years ago. I know, boring right?
"I had plenty of fun in the early days and we spend a good time reminiscing but I'm done with all that."
Harry is now part of supergroup McBusted - made up of McFly and Busted - and the band have just been touring around the UK with a new album under their belt.
"Touring for me now is all about staying fit and healthy so that I'm in the best mood and at the highest energy level I can be for the shows," he continued. "I realised that being hungover every day was making touring unenjoyable."
McBusted - composed of McFly's Tom Fletcher, Danny Jones, Dougie Poynter and Harry, as well as Busted's James Bourne and Matt Willis - joined forces to become a six-piece supergroup in 2013.
aTEEN is available from pocketmags.com/attitude or the Attitude app iTunes.
For exclusive competitions and amazing prizes visit Reveal's Facebook page NOW!