Country star Keith Urban [ tickets ], with actress Nicole Kidman, his wife of four months, by his side, checked himself into a rehab center Thursday night (10/19), according to his publicist.

"I deeply regret the hurt this has caused Nicole and the ones that love and support me," Urban said in the statement. "One can never let one's guard down on recovery and I'm afraid that I have.

"With the strength and unwavering support I am blessed to have from my wife, family and friends, I am determined and resolved to a positive outcome."

According to the statement, Urban has postponed all planned promotional appearances in support of his forthcoming album, "Love, Pain & the Whole Crazy Thing," which is scheduled for release on Nov. 7.

The first affected appearance, apparently, was his planned Friday (10/20) performance at Connecticut's Mohegan Sun Arena as part of the Mohegan Sun Casino's 10th anniversary weekend celebration. Among the stars still scheduled to appear are Jerry Seinfeld, Kevin Costner, Barenaked Ladies, Craig Ferguson and Lily Tomlin.

Urban has been in rehab before, and has admitted to freebasing cocaine in the past.