Jessie J has canceled her U.S. tour dates and postponed several U.K. and European shows to undergo breast cancer surgery. "So, as some of you may know, I just had breast cancer surgery eight weeks ago. Some of you may not, so that's one thing," the singer, 37, said in a video shared via Instagram on Thursday, August 28. "The second thing is, unfortunately, I have to have a second surgery, nothing too serious, but it has to be done before the end of the year, and unfortunately, that falls right in the middle of a tour that I had booked.