Watch: Magic Johnson laments turning down Nike stock on 'Ellen'

Magic Johnson has done very well for himself financially, but there's one business deal he didn't make that still haunts him to this day.

During a Wednesday appearance on "The Ellen DeGeneres Show," Johnson recalled how, leading up to the 1979 NBA Draft, he received a stock offer from Phil Knight, who had just started Nike. Johnson had little knowledge of stocks at the time and ended up turning down the deal.

"Boy, did I make a mistake," Johnson said. "I'm still kicking myself. Every time I'm in a Nike store, I get mad. I could've been making money off of everybody buying Nikes right now."

Johnson also opened up to DeGeneres about his son, EJ, coming out as gay.