Meester gave birth to a baby girl they’re calling Arlo Day on August 4 in Whittier, California.
The couple managed to keep the news quiet for over seven weeks — no surprise, since they were also tight-lipped about their wedding last year.
Leighton has had parenthood on her mind for a while. She told Nylon in November, “Most people I know are starting to get married. It’ll be kids next. I like the grown-up stuff. I like having a house. I’ve got dogs.”