Pompeo confirmed the new addition with an Instagram post on Thursday, in which she shared an adorable photo of Ivery snuggling their son. She also revealed the child's name: Eli Christopher Ivery.
"Chris Ivery just fell a notch," the actress captioned the sweet snap of father and son. "I've got a new guy."
In a statement, a rep for Pompeo told People, "Everyone's doing great."
Eli joins big sisters Stella Luna, 7, and Sienna May, 2. Pompeo and Ivery have kept their family life fairly private over the years, and did not announce Sienna's birth until two months after she arrived. They similarly kept Eli's arrival under wraps until this week, when the family was spotted hiking together -- with their newest addition in tow -- in the Los Feliz region of Los Angeles.
Pompeo and Ivery married in 2007, and welcomed Stella in 2009. Sienna arrived in 2014, via surrogate.
Congrats to the new family of five!