VIDEO: Cher Breaks Silence On Chaz's Sex Change: 'He's Very Comfortable Now'

"During the years we have talked about it and I don't really know what made her change her mind," Cher told Letterman. "I still haven't got the pre-nouns right, but she says that's not so important. He had changed his mind, she had changed his mind and then it didn't make very much difference.

"But it kept nagging, and nagging, and one day he said to me, 'I think I really have to do this,'" the two-time Academy Award winner said. "The day that we talked about it, really talked about it seriously, I said, 'If you have to do this you just have to do it.' I wasn't always able to be quite as calm through the process, but that day I was so calm, and just thought, 'This is what has to happen.'

In an unusually candid exchange for Letterman’s show, Cher explained how Chaz's sexuality figured into his decision to switch genders.

"She was a lesbian - she still is - but it's not the same now,” Cher said. “She has a beautiful girlfriend. But it's not the same thing as being a homosexual, you feel as if you're in the wrong body.

“I was saying to someone the other day, 'I really like being a woman, I feel so comfortable in my body, and if I woke up and I was in a man's body, I'd think, 'Oh my God, I've got to get out of here,’” Cher said. "And that's the way Chaz felt, it was never comfortable - he's very comfortable now."

She said that others have been supportive in the wake of Chaz's life-changing decision, especially with regular stories about the 41-year-old, who lives in West Hollywood with girlfriend Jennifer Elia, sporadically sprouting up in the tabloids.

"A lot of people have come up to me and said Chaz is very brave, because to make this decision with me as your mother, it's difficult, because you're in the limelight, there's no place you're going to hide," Cher said.