In a surprise announcement on Thursday, Oct. 2, 'Grey's Anatomy' star Ellen Pompeo revealed that she and her husband welcomed a baby girl named Sienna May Ivery.

Us Weekly reports that Sienna was born through a surrogate and that the couple kept their plans for a second child a secret until today. "Sienna was born via surrogate & I would like to thank my whole @ShondalandTV family for helping us enjoy these first few weeks privately." @ShondalandTV is the Twitter account for the production company behind 'Grey's Anatomy,' led by show creator Shonda Rhimes.

Pompeo, 44, posted the following photo on Instagram with the caption: "Sienna May Ivery welcome to the world. We love you more than words can say."

The couple, who began dating in 2003 and married in 2007, also have a daughter named Stella Luna, who was born in 2009.

Congrats to Pompeo and Ivery on their new bundle of joy!