In a new interview with The Sun, the 58-year-old America's Got Talent judge reveals he fainted and tumbled due to low blood sugar.
"I'd gone to get some hot milk because I felt ropey," he recalls. "On the way back upstairs, I just remember feeling really dizzy. Next thing I know, someone was putting a neck brace on me and I had a terrible headache, which must have been from me hitting the stairs. I was worried at first that I’d done some real damage."
"But I'm on the mend now," he continues. "I know I was very lucky I didn't hurt myself seriously. It could have been a lot worse. I must say, everyone at the hospital was incredible. I'm truly grateful."
Since the health scare, Cowell has made a vow to take better care of himself for the sake of his 3-year-old son, Eric.
"Sometimes we get a reminder that we're not invincible, and this was certainly mine," he shares. "It was a huge shock. "They think I fainted because I had low blood pressure. So, I have got to really take good care of myself to sort that out."
"After all, I am a dad and have more responsibility than ever," he adds.
As ET previously reported, Cowell was taken out of his London home on a stretcher and transported to the hospital by ambulance, where he underwent tests throughout the morning before returning home. Cowell’s girlfriend, Lauren Silverman, was in New York at the time of the incident.