During Monday’s episode of On Air with Ryan Seacrest, the longtime radio host broke down in tears while detailing his dad’s struggle with the disease. Seacrest,

50, shared his father’s battle as he and his co-hosts were congratulating beloved producer, Dennis Clark, on the announcement that he was now in remission.

“I haven’t shared this on the air because it has been very private for me and my family as it was something that was extremely hard to see with my father,” Seacrest said, adding that he has a “very close relationship” with his dad, who will turn 81 in a few days.