I'm looking for an old Whenever Wherever performance where Shakira screwed up the lyrics towards the end. She didn't realize it was time to sing "you've got me head over heels" and started singing "you'll never have to wonder" instead. She immediately realized her mistake, but it was too late to change it, so she rolled with it and sang the line in a different way. I'm pretty sure only hardcore fans even noticed.
If I remember correctly, this was during the Laundry Service era and it was a TV guest performance.