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Country music singer Luke Bryan apologized today for reading the words to the "Star Spangled Banner" off his hand while singing at the Major League Baseball All-Star game.

Bryan received major criticism for writing the words to the song on his hand and was even called "unpatriotic" by some offended by the event.

"Luke Bryan's version of the national anthem @ the All-Star game last night was an epic fail. He needs to learn respect & remember the lyrics!" one person tweeted.

But Bryan was quick to defend himself with a series of tweets.

"I had a few keys words written down to insure myself that I wouldn't mess up. I just wanted to do my best. I promise it was from the heart," he wrote.

He later added: "If I offended anyone with my approach I sincerely apologize. Anytime I sing the anthem it is an honor and my heart beats out of my chest."

While some remained critical of the singer, Bryan's fans came to his defense.

"@LukeBryanOnline the national anthem is one of the hardest things to sing, let alone to do it in front of thousands and millions watching," one fan wrote.

"@LukeBryanOnline Honestly, it says a lot that you made the effort to do that. I don't doubt your sincerity or devotion to our country," another fan tweeted.

Bryan is also under fire for checking his watch during the song and again responded with a tweet.

"I did check my watch because I knew the stealth bomber would fly over 2 minutes in and I knew a started a little late," he wrote.

Bryan sang the National Anthem in Kansas City, Mo., where the National League beat the American League, 8-0.

Though the singer's mistake got more attention than the shutout, Bryan is not the first - and not likely to be the last - to screw up during the national anthem.

In January, Aerosmith's Steven Tyler endured countless jabs after screaming the song before an NFL game.

Pop singer Christina Aguilera apologized after she flubbed the national anthem during the 2011 Super Bowl, saying she'd gotten "caught up in the moment."

In 2009, pop singer Jesse McCartney skipped multiple verses of "The Star Spangled Banner" while performing at a NASCAR event in California.

And like Bryan, crooner Michael Bolton broke from his overly passionate performance to look at crib notes scrawled on his hand at Boston's Fenway Park in 2003.