Actress Julia Stiles and her husband, Preston J. Cook, welcomed their first child together in October, but she only announced the news on Instagram a month after.

People reported that the "Save the Last Dance" actress posted on Instagram Nov. 21 an image of Cook's thumb being grasped by newborn Strummer Newcomb Cook.

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“Strummer Newcomb Cook, born October 20, 2017. Thanks and ever thanks to the extraordinary Doctors, Nurses and staff at Mount Sinai for helping bring this utter joy into our lives. ‘Hello, World!’” she captioned the post.

The very private star announced her marriage and pregnancy in a Sept. 26 Instagram post. Wearing a white dress and cradling her bump, Stiles's wedding ring could be seen, as well as Cook's hand -- with a rose gold band -- on top of her belly. UsWeekly reported Stiles and Cook were engaged on Christmas Eve 2015 in Isla Grande, Colombia. The met on the set of the film "Blackway," which was screened at the Venice Film Festival in 2015.

“Who doesn't love a shotgun wedding?” the post read.

The "10 Things I Hate About You" actress confirmed her pregnancy in June. She documented her pregancy in occasional instagram posts, including one in which she went camping at nearly eight months preganant.