DENVER (CBS4) – One of the most famous singers in America took the witness stand Thursday in a civil trial in Denver federal court.

Taylor Swift told the court she was certain former KYGO disc jockey David Mueller — known as “Jackson” on air — put his hand on her read end.

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“It was a definite grab, a very long grab,” she told the jury of six women and two men. “I do not want people to stick their hands up my skirt and grab my a– during my meet and greets.”

Mueller is suing Swift, claiming he lost his job over false claims. Swift is countersuing, claiming she was a victim of assault and battery.

“He latched onto my bare a– cheeks as I moved away from him visibly uncomfortably,” she said.

Swift was called to the witness stand by the attorney for Mueller. Mueller’s lawyer pressed Swift on why her body guard did not intervene, asking “It’s odd why (the bodyguard) let this ‘big drunk’ guy put his hand under your skirt, latch on, and get away?”

Swift replied the bodyguard was not in a position to see exactly what happened.

When asked about others who had their picture taken with Swift prior to Mueller, the singer said, “I know none of them grabbed my a– under my skirt.”

In an angry tone, Swift testified, “I’m not going to let you or your client in any way make me feel like this is my fault. It isn’t.”

Swift’s testimony lasted one hour. There were no questions from her attorney.