The music icon loved the cancer survivor's moving Amazon Prime Video documentary, "Val", and the film took her right back to her hot and heavy romance with the "Top Gun" star, which caused quite a stir at the time.
"He was so young," she tells People magazine of meeting Kilmer in 1981.
"Was he 22? What was I? I don't know. Thirty something. It was a bigger deal back then."
Cher, who would go on to date 22-year-old Rob Camilletti when she was 40, tells the magazine, "The truth was if I hadn't gone out with younger men, I would have never had a date. Younger men weren't intimidated by older women. But older men in my age category, they weren't having it."
Val wasn't remotely worried about dating an older woman. "He wouldn't be ashamed or think it was anything. He was a free spirit," she shares. "We called ourselves Sid and Ethel. Val didn't want to yell 'Cher' and I didn't want to yell 'Val.' "
Despite being "madly in love," the duo eventually split.
"I don't know how we stayed friends, we just did. We didn't try. We just were," she says.
Kilmer has credited his former love with really helping during his difficult health battle, writing in his 2020 memoir, "I'm Your Huckleberry: A Memoir", "Cher stepped in and stepped up."
And the "Believe" hitmaker can't believe how brave and funny Val remained as he fought throat cancer.
"He was at my house a lot of the time he was sick. He was brave the whole time. I saw how sick he was," she explains.
"Once when the paramedics showed up after he was so sick and coughing up blood, he looked at me and I looked at him and we both knew what we were thinking."
"Because those guys are so handsome. When one of those paramedics comes to your house, you just know you're going to see somebody who's really cute."
It wasn't all love and roses, she notes, admitting he can still "be a brat."
"But you forgive him. You forgive him everything," she adds. "I loved him - and I love him."