Singer Natalie Cole is “resting comfortably” after undergoing kidney transplant surgery yesterday at Cedars-Sinai Medical Center in Los Angeles, her reps said in a statement today. Cole, 59, has been receiving kidney dialysis treatment three times a week as she toured the world in support of Still Unforgettable. Per doctor’s orders, she will postpone her summer concert dates while recuperating for the next three to four months.