Sharon Osbourne was a judge on "America's Got Talent" from Seasons 2 through 7, and left the show in July 2012.
Osbourne says the reason she left was not because of the show, but because of the network.
"I left. And that's the truth. I left because NBC, not because of the show. I had my own problems with the network. I don't know about any of her (Union's) concerns about the show."
"Obviously, there wasn't anybody of color on the panel when I was there. So I honestly can't say. But when I was there it was, you know, a great show to work on," Osbourne adds.
Osbourne acknowledges that her experience on the show was not like everyone else's.
"Everybody's experience on a show is different, and I was at that show for six years. I didn't get let go, however, I left" she says, during a visit to "The Talk."
Union was fired from the show after one season. The actress had raised concerns about a joke that Jay Leno had said backstage while he was a guest on the show.
In 2012, Osbourne said she left "America's Got Talent" because of the way her son, Jack, was treated at the network.
He was supposed to work on a show called "Stars Earn Stripes," but she said he was let go after he was diagnosed with multiple sclerosis.
"I just can't be fake. It's discrimination, and it was badly handled," she said in an interview with the New York Post at the time.