A person who has worked with Clemons in the past confirmed Sunday night that Clemons had the stroke. The person spoke on condition of anonymity because the person was not authorized to speak on the matter. The person had no additional information on Clemons' condition.
Clemons, 69, is known as the Big Man in the E Street Band and his sax has been one of the most defining elements of the band's sound. He has suffered from numerous ailments over the last few years. He had double knee surgery and even had to perform from a wheelchair at one point.
But his health seemed to be improving. Just last month, he performed with Lady Gaga on the season finale of "American Idol."
Lady Gaga tweeted Monday morning that "my very close friend + musician on The Edge of Glory, Clarence Clemons is very sick. Can we all make some get well videos?"
Drummer and music industry executive Narada Michael Walden, whom Clemons has called a close friend and spiritual adviser, replied to an email query Monday about Clemons by responding, "Love and prayers to the Big Man! He is our Hero!"
Clemons' nephew, saxophonist Jake Clemons, updated his Facebook status on Monday to say: "Please do not lose Hope!"
Kiley Armstrong in New York City contributed to this report.