Drug addict singer Pete Doherty is set to run the London Marathon next year.The wild Babyshambles rocker has already started training for the demanding 26-mile road race with his former landlord, radio DJ Ralph Bernard.A close source said: "Ralph knocked on Pete's door one day and they went for a run. Despite being completely out of shape, Pete enjoyed it and he's been out again and again. The runs went so well, Ralph suggested that Pete try a marathon."Pete's representatives have not denied the singer is planning to run the gruelling race on April 13, saying: "There is some truth to this, you never know what could happen."The 28-year-old star, who is battling heroin drug addiction, has also been seen meditating and doing press-ups in a bid to clean up his act.The source added: "He thinks that running is a great way to get back in shape, especially after piling on the pounds in rehab."He knows that people will be surprised by his efforts to be healthier but he really wants to turn over a new leaf."Meanwhile, Pete has revealed he has a new addiction, mince pies.The rocker, who performed at Kent's Tap'n'Tin pub at the recently, rejected all alcoholic drinks and insists he is planning a clean-sober Christmas.He said: "It is going to be mince pies for me this Christmas. I have got a massive order on the way."