The tatt features the roman numerals "12-31-13," an apparent reference to her New Year's Eve wedding in California, where the Big Bang Theory star and her tennis pro boyfriend made their whirlwind romance official.
Sweeting debuted a similar tattoo a few months ago -- the same roman numerals encased in a heart on his wrist.
Cuoco-Sweeting and her husband are known for their public declarations of affection. Both shared photos of the tennis match on their Instagram accounts.
"What a fun night! Luckiest man alive to have a wife that's just the s%&t!! @normancook," Sweeting wrote.
"Team awesome :) @ryansweething," Cuoco-Sweeting said.
Swim Week Miami Beach 2014 [PHOTOS]