Paul Simon Undergoes Back Surgery After Canceling 2 Shows

We've got a health update from Paul Simon -- the Simon & Garfunkel icon underwent a successful back surgery to alleviate "severe” back pain that forced him to cancel 2 shows last month.

The positive update was released on his official Instagram page Thursday ... though there is a caveat. His team says he needs more time to recover, so his July 7 concert in Long Beach, California is being postponed to the following day.

It seems fans don't have too much to worry about -- the statement says the decision was made out of an "abundance of caution" to ensure PS is ready to hit the stage "at the top of his ability."

The "Bridge over Troubled Water" hitmaker is in the middle of his "A Quiet Celebration Tour," which kicked off April 4 in New Orleans, Louisiana, and is scheduled to wrap up in Seattle, Washington on Aug. 3.