Adele admitted via Twitter her performance at Monday night's Grammy Awards show didn't go as well as she had hoped it would.

She was singing "All I Ask" during the CBS telecast, which honored excellence in all genres of music, when a sound issue arose.

"The piano mics fell on to the piano strings, that's what the guitar sound was. It made it sound out of tune. [Expletive] happens," she tweeted.

"Because of it though... I'm treating myself to an in n out. So maybe it was worth it," Adele added, referring to a famous Los Angeles burger palace.