The late father of NASCAR star Denny Hamlin was diagnosed with a terminal illness before his tragic death in a house fire. Dennis Hamlin, 75, died after a blaze engulfed the North Carolina home he shared with his wife, Mary Lou Hamlin, on Sunday, December 28. The home was owned by Denny, 45, one of the most prolific names in motorsports. Mary Lou, 69, was taken to a local hospital with "life-threatening" injuries, before being transferred to Atrium Health Wake Forest Baptist Burn Center in Winston-Salem, North Carolina, where she is still being treated. In the months leading up to the fire, Dennis' poor health had been a major theme of Denny's career. Who Are Denny Hamlin's Parents? Meet the NASCAR Star's Mother and Father Specifically, Denny spoke about the motivation he felt to finally win a NASCAR Cup Series championship while his father was still alive. "I know for a fact this is my last chance for my dad to see it," Denny told the Associated Press in October. "I don't want him going and never getting to see the moment." Denny also spoke about his father's health after winning at Las Vegas Motor Speedway in September, recalling a recent conversation he had with his father at his parents' home. "He was just so happy and he always tells me I'm the best, no matter if I win or not, he always says I'm the best," Denny said. "He's a big hype guy and I sat in his garage and talked with him, he's got all my old memorabilia and it's just good to reminisce. He's a reminiscent guy and right now I am just cherishing those hours that I have with them each week." Denny added, "He's the one that got me into racing. Just took me to a race track when I was 5, then made all the sacrifices financially to keep me going. Sold everything they had. We almost lost our house a couple times. Just tried to keep it all going." Courtesy of Mary Lou Clark Hamlin/Facebook The Hamlin family did not disclose the specifics of Dennis' illness. Last year, Dennis recalled a promise made to him by NBA legend Michael Jordan, who co-owns 23XI Racing with Denny. "He pulls up in his Lamborghini and he reaches down in the side door of it, pulls out this cigar," Dennis said on an episode of Netflix's NASCAR: Full Speed. "He signed it for me and wrote me a little letter that says, 'Break it when we win the championship. So I'm supposed to break that thing and smoke that cigar. So I guess that's what I'm gonna do." Greg Biffle's Holiday Card Arrived at Friends' Homes After Fatal Plane Crash Dennis added, "I'll give you everything I own, every car in this garage, the house, whatever, if I could make that happen." Sadly, Denny came up just short last season, finishing in 2nd place in the NASCAR Cup standings, just four points behind winner Kyle Larson. The fire at the Hamlin home broke out around 6:20 p.m. ET on Sunday, with fire crews taking approximately two hours to extinguish the blaze. No cause for the fire has been given and the investigation remains ongoing.