(NEXSTAR) – Michael Bolton is recovering, the singer said Friday, after discovering he had a brain tumor that required an emergency operation.

“Just before the holidays, it was discovered that I had a brain tumor, which required immediate surgery,” he said on Instagram. “Thanks to my incredible medical team, the surgery was a success.”

Bolton said he planned to take a break from touring for the next few months as he focused on recovery. At the time of his announcement, his website still showed tour dates planned for Florida, California, Ohio, Illinois and Ontario, Canada, in February, as well as additional concerts through spring. It’s not clear how many shows Bolton will cancel or reschedule.

“It is always the hardest thing for me to ever disappoint my fans or postpone a show, but have no doubt I am working hard to accelerate my recovery and get back to performing soon,” he wrote.

The 70-year-old singer has been nominated four times for the Grammy Award for best male pop vocal performance. He won in the category twice: once in 1990 for “How Am I Supposed To Live Without You” and then again two years later for “When A Man Loves A Woman.”

On Friday he thanked his fans for their support over his long career. “I am beyond grateful for all the love and support you have so generously shown me through the years,” he wrote. “Know that I’m keeping your positive messages in my heart, and I’ll give you more updates as soon as I can.”