CSI's Marg Helgenberger: Justin Bieber Was "a Brat" on Set

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Marg Helgenberger should watch her back among the Beliebers.

The CSI star may be among the few not smitten with Justin Bieber, who guest starred on her smash CBS show last fall.

"Justin Bieber wasn't bad," Helgenberger, 52, said during an interview with a French radio station (as reported on Huffington Post). "He had never acted before. I shouldn't be saying this, but he's kind of a brat," she added.

"He was actually very nice to me, but he locked one of the producers in the closet. And he put his fist through a cake that was on the table," Helgenberger also noted of the singer, 17.

"I am pretty open to whoever comes on the show," she continued. "If someone is a jerk, that bothers me. If they're a so-so actor, it doesn't bother me. [Bieber] is actually better than you'd think!"