Cyndi Lauper mixed up the words to America's National Anthem during a live TV performance at the U.S. Open semi-finals on Saturday.
The "True Colors" hitmaker flubbed the lyrics as she sang "The Star-Spangled Banner" before the women's match between Serena Williams and Caroline Wozniacki.
Lauper sang, "O'er the ramparts, we watched as our flag was still streaming," instead of "O'er the ramparts we watch'd were so gallantly streaming."
The singer later took to her Twitter.com page to explain her mix-up, admitting she felt emotional because she had performed immediately after a moment of silence was held for 9/11 victims.
She writes, "Whew, I just did the anthem for the US open. It was an awesome experience. I got choked up in the middle remembering 9/11...
"The moon shone done (sic) on us and I tried to say a prayer at the same time... I hope I didn't mess up too bad. I wanted it to be comforting."
Pop star Christina Aguilera was left red-faced after botching the same lyrics at the Super Bowl earlier this year.