Adorable USA Freedom Kids Prepare to Take on Donald Trump in Court Over Nixed Appearance

The father of one of the girls said Trump had booked them, but that wasn't the case when they showed up in Iowa.

The young singing group that became a sensation after appearing at a Donald Trump rally performing a song in his honor may sue the GOP presidential pick.

Read: USA Freedom Kids: Trump Says He'll Listen to Our CD All Night

The USA Freedom Kids captured the country’s hearts with their patriotic renditions after the trio opened the rally for Trump, earning a ton of applause from his supporters.

They did so well that they were invited to another Trump rally, according to Jeff Popick, the father of the youngest 'Freedom Kid.'

Popick told Inside Edition the Trump campaign later rescinded the invitation, after the group had traveled to Iowa on their own dime.

"We will be filing a lawsuit," he said. "They promised us that the girls could perform other songs and that the exposure, in their words, would be huge."

Popick even wrote the pro-Trump song “Freedom’s Call” which gained them national attention.

"That was an agreement we entered into on the phone at 6:30 at night before the next day when his rally was taking place in Des Moines, Iowa. It was essentially a verbal agreement," Popick claims. 

Read: Kids Group Performs Donald Trump Theme Song At Campaign Rally

"There were planned 'changes' and we were to sit in the audience of this rally and we were instructed to not even speak to the media," he told Inside Edition. 

Popick says he's not thrilled about going up against Trump, but he will if that's what it takes. He really just hopes the kids will get another chance to perform.

Watch: Donald Trump Lets Loose While Live Tweeting DNC, Slams Speakers