Rachel Platten, 'One Direction' songwriter slams 'unauthorised use of band's songs at Trump's Inaugural Ball

Nobody, except Rachel Platten, was more surprised to hear her popular single, 'Fight Song', being played by 'The Piano Guys' at President Donald Trump's inaugural Freedom Ball..

The artist was furious at the band for playing the song without her permission.

The singer and songwriter took to Twitter to express her outrage, "While I respect the office of the President and the peaceful transfer of power."

"I want to make clear that at no point did the Piano Guys . ask for permission, nor did I or anyone on my team know of, approve or endorse their decision to play Fight Song tonight," added the singer in a series of tweets.

At the event, the Utah-based music group also played a mash-up of "Amazing Grace" and "Fight Song", which was the anthem at many Hillary Clinton campaign rallies.

It was not only Platten, who was frustrated with The Piano Guys, Savan Kotecha, the songwriter of One Direction's "What Makes You Beautiful," also threatened to sue them after his song was played at the same inaugural ball.

Kotecha took to Twitter and wrote, "They were absolutely NOT given permission to use WMYB at the inaugural ball. I will be looking into taking action." There's nothing I can do re WMYB now, but the song was written out of love for my wife. It's just heartbreaking that it was used to celebrated (sic) a man who stands for divisiveness."

The collection of performers at Friday's event included, singer Sam Moore, Silhouettes, The Rockettes, Pelican 212, The Piano Guys, Circus 1903, Cache Olson, Lexi Walker and Erin Boheme.

President Donald Trump along with wife Melania also danced to a live cover of "My Way" - famously first recorded by Frank Sinatra - at the Freedom and Liberty Balls and also danced to a rendition of Whitney Houston's "I Will Always Love You" at the Armed Services Ball.