Pop star Taylor Swift has taken the witness stand to testify against the former Denver DJ who says she falsely accused him of groping her.

Her testimony began on the third morning of what’s expected to be a nine-day trial, and on the heels of emotional testimony from her mother, Andrea Swift, and Frank Bell, a member of her management team.

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David Mueller, who used to work at KYGO, is suing the 10-time Grammy winner for an unspecified amount of money, claiming that what he alleges was a false accusation has prevented him from finding another radio job.

Swift countersued for battery and assault. Her mother told the court that since the June 2, 2013 incident at a meet-and-greet at the Pepsi Center, the star has changed how she interacts with fans.

During her testimony, Swift said at the meet-and-greet, she felt Mueller “grab onto her ass cheek underneath her skirt, then lurched away as fast as he could.”

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“It was a very shocking thing that has never happened to me before,” Swift said.

Swift said she didn’t report the incident until after the meet-and-greet because she didn’t want to ruin the experience for other fans in line.

"I have experienced every degree of awkward first encounters," Swift said. "This was not jostling. He grabbed my bare ass."