Fergie has defended Christina Aguilera after she fluffed a line of the US national anthem at the Super Bowl.

The Black Eyed Peas star - who also performed at the annual NFL showpiece game on Sunday (06.02.11) - understands why the singer made the mistake saying it was only natural that she was "nervous."

She told 'The Dan Patrick Show' on FOX radio: 'I felt for her because, you know what, it's such a huge venue, your nerves just take a hold of you, so I completely understand. She's one of the best singers of our time, so nobody can Take That away from her. You get nervous at these things; she's human!

Christina, 30, was given the prestigious task of performing the Star-Spangled Banner to open the proceedings ahead of The Game between the Pittsburgh Steelers and the Green Bay Packers in Arlington, Texas but shocked onlookers with her mistake.

Instead of the correct line "O'er the ramparts we watched, were so gallantly streaming?" she sang "What so proudly we watched at the twilight's last gleaming."

However her celebrity pals were quick to take to twitter to defend her with Nicole Scherzinger, who attended the game writing: "Xtina just killed it 'sangin'! Sounded amazing here," and Black Eyed Peas will.i.am saying "Xtina sing'n wonderful (sic)."