Grammy-winning country music star Keith Urban has checked into a rehabilitation treatment centre, with actress wife Nicole Kidman "at his side," the singer's spokesman said on Friday (October 20). "I deeply regret the hurt this has caused Nicole and the ones that love and support me," Urban said in a written statement released through his publicist. Urban did not disclose the nature of his treatment. He has acknowledged an addiction to cocaine in the past. "One can never let one's guard down on recovery and I'm afraid that I have," Urban said in the statement. The 38-year-old singer added that he was "calm and optimistic about the future and finally coming to terms with the reality of my condition." Publicist Paul Freundlich said that as a result of the treatment, Urban would suspend appearances for the release of his CD "Love, Pain & The Whole Crazy Thing," which is scheduled to hit stores on Nov. 7. Freundlich said Urban "voluntarily admitted himself to a treatment rehabilitation centre last night with his wife by his side." Urban and Kidman, 39, were married last June in Sydney.