"I probably shouldn't say this, but he was kind of a brat," Helgenberger said in an interview with French radio show Le Grand Direct des Medias on Friday when asked about the teen phenom's time on the set.
She continued, offering specific examples from when Bieber filmed guest appearances on "CSI." "He locked one of the producers in a closet," she said. "And he put his fist through a cake that was on the craft services table."
Bieber's response? "It's kinda lame when someone you met briefly and never worked with comments on you. I will continue to wish them luck and be kind. #killemwithkindness," he wrote. "Even last week they had me scolded on a plane in the news because i wasnt in my seat fast enough. She was right and i sat down. That's news? I know who i am and sometimes people r just going 2 say what they want. Keep ur head up and be the man ur mama raised. #killemwithkindness.
"Rumors are just that ... rumors," Bieber continued. "In the end if you just be kind and be yourself people will know who you are. That goes for anyone i think. as for now ... we are in the JUNGLE!! Dont spread gossip and dont spread rumors about others ... im a kid and i know that. #respect."
He then tweeted a link to a video clip of "The Lion Sleeps Tonight" from "The Lion King."
Reps for both Bieber and "CSI" had not responded to MTV News' request for comment by press time.
MTV News spoke to "CSI" producer Carol Mendelsohn last year, after Bieber had taped his first appearance on the show. (He appeared again earlier this year.) She had only kind words about the actor.
"I thought that he did a really good job. We only had Justin for a day, for 10 and a half hours, and he had a lot of work crammed into those 10 and a half hours," she said, adding, "It's hard for any accomplished, mature actor to come on the set and fall right into character and do your work, so kudos to Justin."