"Been AWOL from Twitter. I totally have a good reason: TINY HUMAN #3 is here and she's perfect! Babies are good. Life is good," Rhimes tweeted Wednesday night. "#2shows3kids."
No other details about the baby, such as her name or birth date, were immediately available.
The "Grey's Anatomy" and "Scandal" show-runner previously adopted daughters Harper and Emerson, EW.com said.
Celebrity Families of 2014 [PHOTOS]