Billie Lourd gives birth to a son

Sept. 25 (UPI) -- American Horror Story, Booksmart and Star Wars actress Billie Lourd is a first-time mother.

"Introducing: Kingston Fisher Lourd Rydell," Lourd captioned Thursday's Instagram photo of her newborn's tiny feet, sticking out from a fluffy blue blanket.

Lourd, 28, announced in June that she was engaged to actor-producer Austen Rydell, but she did not publicly discuss her pregnancy, so the baby announcement came as a surprise to many.

Her AHS co-star Emma Roberts wrote in the comments section on Lourd's post: "Screaming!!! Love you guys so much."

"Congratulations Mama And Papa and family!" AHS actor Matt Bomer said.

"WAIT WHAT???" Lourd's fellow Scream Queens alum Jamie Lee Curtis posted.

Billie's uncle, Todd Fisher, told E! News: "I was very touched Billie chose to honor her mother by naming her son Kingston Fisher. It was very unexpected. Billie has been known as Billie Lourd her whole life. It is a very loving thing to give that homage back to Carrie."

Lourd is the daughter of Star Wars legend Carrie Fisher and the granddaughter of Singin' in the Rain star Debbie Reynolds, both of whom died in 2016.