In a 2013 interview with GQ’s Chris Heath, Mars reminisced about his early days of gambling when he frequented the Commerce Casino in Los Angeles, long before he became famous.

"I used to be like a loudmouth. You know the guy, people would want to take his money. If you do get them to lose, they're out for you, they're gunning for you,” Mars said at the time. “And that's when they're weak. And that's when you jump or pounce on them.”

In the interview Mars also opened up about the first time he visited a casino when he was 19-years-old.

"I remember my first bet, my hand was shaking, and a guy called me out on it and embarrassed me,” he said, admitting he lost a hundred dollars he couldn’t afford to lose. "You gotta lose. You just have to lose to win, to understand."

During his Carpool Karaoke episode for the Late Late Show with James Corden in 2016, Mars briefly revealed that he was able to make rent while living in L.A. by playing cards “for a little while.” You can catch this moment at the 13 minute mark here.