Credit: C.Smith/ Photo: Kaylee DeFer Smiles at Fashion's Night Out in New York City on September 8, 2011

Gossip Girl star Kaylee DeFer is now mama to a baby boy!

According to Us Weekly, Kaylee, 26, and her musician boyfriend Michael Fitzpatrick, 43, welcomed their first child on Friday, September 20.

Their son, Theodore Ignatius Fitzpatrick, was reportedly born at 10:14 p.m., arriving at 8 pounds and 13 ounces. "Kaylee was a rock star!" Michael said.

The Fitz and the Tantrums frontman actually had to cancel a Friday night show in San Diego, telling fans "there is a baby Fitz coming!"

Kaylee (who played Ivy Dickens on GG) was previously engaged to Mike Pereria. When confirming her pregnancy back in May, she told Us Weekly it was a surprise since they weren't planning to get pregnant. They also didn't have any plans to marry, they were just enjoying the pregnancy.

Baby Fitz may not have been planned, but they both sound excited and happy to welcome him into the world. He was meant to be in their lives. Congrats to the growing family!

Source: Us Weekly