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Katie Couric joined other celebrities last night for a screening of the new documentary Bully and disclosed that a member of her own family was subjected to severe bullying.

"I know my sister was bullied when she was younger and it was really, really upsetting to our whole family," Couric told ET while attending a special Bully screening -- hosted by Academy Award winner Meryl Streep -- at the Paley Center for Media in New York.

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The longtime journalist said that although she personally was too young to remember specific instances of her sister's bullying, the experience is still part of family discussions. "My mom... we still talk about what you do when a whole group of girls gangs up on you. And sometimes talking about it or going to the authorities makes it even worse."

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Bully -- set for limited release beginning next Friday March 30 -- explores the difficulties faced by bullied kids and reveals the sometimes endangered lives of the youngsters, who come from a variety of geographic, racial and economic backgrounds.

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"I really applaud the filmmaker who is documenting real cases of bullying because I think you need to hear the personal stories to bring it home -- and sometimes it's too late," Couric said. 

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Watch the video to also hear director Lee Hirsch talk about the outpouring of celebrity support for the film, as well as our interviews with domestic diva Martha Stewart and The Good Wife's Archie Panjabi.