Comedian Howie Mandel is best known for his hilarious quips, but it was no laughing matter when the “America’s Got Talent” judge was diagnosed with an irregular heartbeat.

The 59-year-old star is living with a heart condition known as nonvalvular atrial fibrillation (AFib), which was estimated to affect approximately 6.4 million Americans in 2014 alone. Like many of us, Mandel never heard of AFib, prompting him to team up with Bristol-Myers Squibb and Pfizer for an educational campaign called “Fibs or Facts.”

But what exactly is AFib and how can we really test our knowledge? Mandel spoke with FOX News Magazine about his diagnosis, what his health is like today, and why everyone should check out FibsOrFacts.com for a fun quiz to help you get started.

See the exclusive video above and don’t forget to check out season 10 of “America’s Got Talent” tonight at 8 p.m. EST on NBC.