John Mellencamp gave a rare update on his daughter Teddi Mellencamp's health as she battles stage 4 cancer. "It's not f***ing fun," John, 74, said of Teddi's cancer journey during the Wednesday, January 14, episode of the "Joe Rogan Experience" podcast. "She's got cancer in the brain, and she's suffering right now." The "Jack & Diane" singer noted that Teddi, 44, is "really sick" after being diagnosed with stage 4 brain cancer in early 2025 following a battle with melanoma in 2022.