The Charlotte Hornets center had April 4, 1896 written in his Twitter biography for his birthday, but actually turned 24 years old Tuesday.
Kaminsky is averaging 11.9 points and 4.6 rebounds per game in his second season for the Hornets.
Skittles noticed the blunder and sent him a cake made of the candy in the shape of a big No. 121.
"When you list your birthday as April 4, 1896 on Twitter and @Skittles takes you seriously... Thanks for the 121st birthday cake," Kaminsky tweeted.
"@FSKPart3 I don't mess around when it comes to birthdays," Skittles tweeted. "You should see what I'm planning for your 200th!"
The move comes a day after Kaminsky got into a heated debate with ESPN's Dan Dakich on Twitter. Kaminsky argued that universities exploit college athletes. Dakich disagreed.