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Actor Jonah Hill was contrite this morning after using a gay slur during a confrontation with a paparazzo over the weekend.

"I'm not at all defending my choice of words, but I am happy to be the poster boy for thinking about what you say, and how those words, even if you don't intend them in how they mean, they are rooted in hate, and … I shouldn't have said that," the "22 Jump Street" actor told Howard Stern this morning.

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Hill explained that he was being hounded by a paparazzo when he made the anti-gay remark. TMZ posted a video of what appeared to be Hill responding to the photographer.

"This person had been following me around all day, had been saying hurtful things about my family, really hurtful things about me personally," the actor told Stern. "I played into exactly what he wanted and lost my cool. And in that moment, I said a disgusting word that does not at all reflect how I feel about any group of people."

Hill, 30, was especially upset about his reaction because, he said, "From the day I was born, and publicly, I have been a gay rights activist."

The California native said he grew up with gay family members and one of his best friends is gay. "I'm good at making movies, I'm not good at being a famous person," he said.

"I'm happy to take the heat for using this disgusting word," he added. "What I won't allow is for anyone - it would break my heart to think that anyone would think, especially for all the work I've done and all the loved ones I have, that I would be against anyone for their sexuality."