A US country singer has apologised and admitted she was drunk when she performed an off-key version of the national anthem.

Ingrid Andress’s rendition at a baseball game was widely panned and drew gasps from the crowd after one particularly shaky high note.

She was opening the show at Monday’s Home Run Derby in Arlington, Texas, and it didn’t take long for people to express their shock on social media.

“I’m so sorry, I’m sure Ingrid Andress is a wonderful person, but that was one…