"They think I'm crass or crude and rude . . . because they can't see beneath the person," she said.
"They believe what they read about me or think I am my characters. People can be terrible.
"I have had people tweet, 'Get that fat c*** off the television.' It is cyber-bullying. I'm in character and I'm having a laugh. I want to entertain people; I'm not being nasty. I have an audience with big ratings."
The Mohill native added: "What I'm trying to say is that I am a person separate to my characters. Just because I'm a woman, I feel that I can't say what I want to say. I have always said, it is not that hard being a female comedienne but recently, I do feel it can be."
She is currently riding high in her professional life, thanks to the success of her twice-weekly chat show which she co-fronts with Brian Dowling.
Katherine has enticed a string of well-known celebrities to come onto her show, including Kerry Katona, Paul Daniels and Denise Welch.
But she reveals to Suburbia magazine how the passing of her beloved father Tom nearly two years ago knocked her for six and she has only recently felt like herself again.
She said time in America helped her find new strength.
"I remember looking in the mirror and physically seeing the light go out in my eyes."
"But that light is back but I had to work hard at reigniting it. I went to New York this year and I have to say it brought the spark back on every level.
"The magic of the Big Apple did it for me. I attended the New York Film Academy and remembered why I became an actress. I found the hunger and love for representing a cusp of society -- women."
She is now bringing out her first album, which she began writing after her father passed away.
Entitled Settling Dust, it's due to hit the shelves on February 8. "It all came naturally as at that time, I didn't feel for comedy. It is a dream project."
Read the full version of this interview in Suburbia magazine, out now.