Reigning "American Idol" champ Scotty McCreery and runner-up Lauren Alaina BOTH suffered very public singing mishaps on Thanksgiving.

Scotty was at the Macy's Thanksgiving Day Parade, where he was supposed to be lip-synching to his song "The Trouble with Girls". But when the cameras zoomed in, the vocal track started without him.

It wasn't even close... he didn't even have the microphone up to his mouth...but Scotty quickly jumped in, and pretended to sing the rest of the song.

But Lauren topped that by messing up the National Anthem before the Detroit Lions / Green Bay Packers game. She was singing LIVE...but she tripped over the lyrics in the second line, and STOPPED for a few seconds.

She picked it back up...and finished without any other problems.