Carrie Fisher's daughter Billie Lourd announces birth of 1st child with sweet photo

Surprise! Billie Lourd announced Thursday she had welcomed her first child, a son, with fiancé Austen Rydell.

The daughter of the late Carrie Fisher revealed the big news on Instagram, with a photo of her newborn's tiny feet. The post came as a surprise to fans, as Lourd never publicly announced her pregnancy.

In the caption, the 28-year-old new mom told her 1.4 million followers she and Rydell, 28, had named their bundle of joy Kingston Fisher Lourd Rydell.

Kingston is wearing what looks like a space-themed onesie in the snap, so it appears the force is strong with him -- after all, both his mom and his grandmother starred in the "Star Wars" franchise.

Lourd's "Scream Queen" co-star Emma Roberts, who is currently expecting her first child, reacted with excitement in the comments, writing, "Screaming!!! Love you guys so much." She also got a "mazel tov" and a "congrats" from her two "Booksmart" co-stars Beanie Feldstein and Kaitlyn Dever, respectively.

The "American Horror Story" actress and Rydell got engaged in June.