Karen Harding appeared to miss her cue as the music for God Save the Queen began at Wembley, before joining in part way through
She then took to Twitter to explain the situation
Biggest audience of my life and I get technical difficulties! Argh so sorry Guys," she tweeted before adding: "Mortified!! I don't know what happened."
The 24-year-old was performing ahead of Manchester United's meeting with Crystal Palace on Saturday.
Source : PA