TAYLOR SWIFT SUED BY RADIO DJ :

  Taylor Swift's ass is in the middle of a lawsuit ,a former Denver radio DJ said he got canned after her security accused him of grabbing Taylor's cheeks.

David Mueller says he was attending a Swift concert in Denver in 2013 and was invited backstage. According to  Denver Post, Mueller says he and his Girlfriend took a photo with Swift and then left to enjoy the show.

Mueller says he later ran into a co-worker who was bragging about putting his arms around Taylor and grabbing her butt during his photo op with her.

Here's where it gets interesting ... Mueller says in a lawsuit, he was approached by one of Taylor Swift's security guards who accused him of grabbing Taylor's tush and kicked him out of the arena. Mueller says he was fired from his country music station because of the incident.

He's suing Taylor, although it's unclear if she had any idea any of this mess the accusation or Mueller's firing.