Billie Lourd introduces newborn son in surprise announcement

The American actress paid tribute to her late mother, Carrie Fisher, in his name

epa08204343 US actress Billie Lourd arrives for the 2020 Film Independent Spirit Awards in Santa Monica, California, USA, 08 February 2020. The award ceremony, organized by the non-profit organization Film Independent, honors the finest independent films of the preceding year.  EPA-EFE/NINA PROMMER

Billie Lourd has announced that she has welcomed a baby boy with actor fiance Austen Rydell. The actress chose to keep her pregnancy private.

The American Horror Story star, 28, shared a photo of her newborn's feet on Instagram, and has paid tribute to her mother, Carrie Fisher, in his name.

"Introducing: Kingston Fisher Lourd Rydell," she wrote.

Messages of congratulations have flooded in from fellow stars.

"I love you Kingston," commented Olivia Wilde, while Emma Roberts, who stars opposite Lourd in American Horror Story , wrote: "Screaming!!! Love you guys so much."

Glee star Lea Michele wrote: "He's finally here! So happy for you! Boy moms!" Michele welcomed a baby boy in August this year.

It seems that her pregnancy was not common-knowledge in celebrity circles, either. Actress Jamie Lee Curtis commented: "Wait, what?"

Lourd is engaged to actor Austen Rydell. The couple announced their engagement in June this year.

"She said YES!! (Actually she said “Duhhh”) But I guess that’s even better than yes?!?," Rydell wrote to announce their engagement on Instagram.

Lourd is one of a handful of celebrities to welcome babies this week.

On Thursday, September 24, Dutch-Palestinian model Gigi Hadid announced that she had welcomed a baby boy with boyfriend, Zayn Malik.

Singer Justin Timberlake and actress Jessica Biel have also secretly welcomed their second baby earlier this year, it was confirmed yesterday. The couple are yet to share a photo or announce the baby's name.

Timberlake's Nsync bandmate, Lance Bass, confirmed the couple's baby news to ET.

"The baby is cute of course, it's Justin and Jessica!" he said of the couple's second child. He added that he's had seen pictures but could not share the name, joking, "Justin would kill me!"

The couple are also parents to son, Silas Randall Timberlake, 5.