The American Horror Story star revealed she was expecting her first child in December (16), when she showed off her growing baby bump as the couple attended the 2016 Kennedy Center Honors event in Washington, D.C.

Lily announced the birth of their daughter in a post on Instagram last week (08Mar17) as she marked International Women's Day, although the news had flown under the radar until now.

Alongside a photo of the first-time mum snuggling with her newborn, who was wearing a knitted pink beanie hat, she wrote, "Happy International Women's Day. Today. Tomorrow. Every day. Girls are magic. #internationalwomensday #weshouldallbefeminists #thefutureisFEMALE".

Lily, 34, began dating Hamish in 2013.

The child is the 40-year-old actor's second; he also shares nine-year-old Lucinda Rose with his ex-wife Jessica Goldberg, who he divorced in 2012 after 10 years of marriage.