Cyndi Lauper had a bit of an embarrassing moment when she pulled a Christina Aguilera on Sunday. The pop star flubbed the lyrics to 'The Star Spangled Banner' during a 9/11 tribute at the US Open.

The 58-year-old singer sang the national anthem after the crowd observed a moment of silence for the victims of the attack 10 years ago. However, at the fourth line of the song, the pop star opted for different lyrics.

She sang, "O'er the ramparts we watched, as our flag was still streaming" rather than the actual words, which are: "O'er the ramparts we watched, were so gallantly streaming."

Lauper remained poised throughout the remainder of the song, even though she knew she had mixed up the words. Later, the singer admitted to the mistake on Twitter, citing the emotions of the tragic event as the reason for the error. "I got choked up in the middle remembering 9/11," she wrote. "I hope I didn't mess up too bad. I wanted it to be comforting."

Earlier this year, Aguilera flubbed the same lines while singing Francis Scott Key's poem at Super Bowl XLV. The 'Voice' coach completely omitted the “O’er the ramparts we watched were so gallantly streaming” line and ad-libbed instead. She later said in statement, "I can only hope that everyone could feel my love for this country and that the true spirit of its anthem still came through."

Watch Cyndi Lauper Flub the National Anthem at the US Open