Rocker Aaron Lewis has apologised for singing the wrong words during a performance of America's National Anthem at a baseball game on Sunday night (26Oct14).

The Staind frontman has come under fire from fans after fluffing the lyrics to The Star-Spangled Banner at the At&T Park in San Francisco, California ahead of the San Francisco Giants' World Series clash with the Kansas City Royals.

He has now offered an apology for getting the words wrong and blamed the blunder on nerves.

In a post on his website, he writes, "All I can say is I'm sorry and ask for the Nation's forgiveness. My nerves got the best of me and I am completely torn up about what happened. America is the greatest country in the world. The Star-Spangled Banner means so much to so many, including myself. I hope everyone can understand the intensity of the situation and my true intent of this performance. I hope that the Nation, Major League Baseball and the many fans of our national pastime can forgive me."