Gene Simmons is recovering after undergoing surgery early Tuesday morning to remove several kidney stones.

TMZ reported that the KISS frontman was admitted into Cedars-Sinai Hospital in Los Angeles. The procedure was reportedly non-invasive and only took an hour to complete. A stent was apparently inserted in Gene's urethra, which helps urine flow from the kidney to the bladder, all of which should help him simply pee the stones out.
Gene, 70, is expected to have the stent for a week, and doctors expect him to be free of kidney stones.
It seems that the kidney stones have been nagging Gene for some time, and the condition even forced KISS to cancel a show in mid-September.
"Apologies to the fans in Salt Lake City. We will come back and do the show at a later date," he tweeted on Sept. 13. "The truth is, I have to fly to LA to do a medical procedure. Nothing serious. But it must be taken care of now. Thank you for your good wishes. All is well."

The surgical procedure didn't seem to be weighing too heavily on the rocker on Monday, as he attended the premiere of "Maleficent: Mistress of Evil" in Los Angeles with his children, Nick, 30, and Sophie, 27.