Khloe Kardashian was not happy with the joke Jamie Foxx made at her step-father's expense during the iHeartRadio Music Awards because the two know each other on a personal level.

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On Friday, New York Daily News reported that after Jamie Foxx took a shot at Bruce Jenner, Khloe Kardashian is coming up to bat for her him.

"Bruce Jenner will be here doing some musical performances. He's doing a his and her duet by himself," Foxx said.

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He then clarified that he was only kidding by saying, "busting your b---s -- while I still can."

But that wasn't enough clarification for Kardashian who responded: "I just think it's a low blow. I think it's very mean. I wish him all the best. It is what it is."

And the fact that Kardashian knows Foxx personally makes the comment even worse form her perspective.

"I know Jamie, so I think that's also why that's a really low blow," she said. "But hey, guess that's what he felt the need to do for a little press," the reality TV star said.

According to People, the 65-year-old has apparently been struggling with his identity for years.

"He suffered from feeling a lot of shame about this for a lot of years," the source said. "Just recently, to see a growing acceptance for transgender people. It lifted a tremendous burden off him in terms of feeling alone."

And what helped Jenner the most to come out as transgender was apparently his relationship with ex-wife Kris Jenner.

"She was in charge, and he was just along for the ride. It made him feel like he didn't have to worry so much about his identity, who he was," said the source.

The source said it was nearly three years ago that Jenner knew he could no longer keep his secret to himself.

"He had enough of letting other people dictate how he was going to live," the insider said.