Billie Lourd Introduces Her Baby Girl, Daughter Jackson Joanne— See the Sweet Photo!

Billie Lourd/instagram, Mike Marsland/WireImage

Billie Lourd is introducing the world to her daughter!

The Ticket to Paradise star and actor husband Austen Rydell, both 30, welcomed daughter Jackson Joanne on Monday, Dec. 12, the actress confirmed in an Instagram post providing a peek at the newborn, who joins 2-year-old son Kingston Fisher.

"1️⃣2️⃣✨1️⃣2️⃣✨2️⃣2️⃣ Introducing: Kingston's sister: ✨💖✨Jackson Joanne Lourd Rydell ✨💖✨," Lourd captioned the shot, which shows the newborn from the neck down, with her little hands in front of her as she wears a ribbed, neutral long-sleeved onesie.

While Kingston's middle name, Fisher, is an ode to Lourd's late mom, actress Carrie Fisher, the couple's newborn baby girl's middle name seems to pay tribute to Rydell's late grandmother, actress Joanne Linville.

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The actress's father, Bryan Lourd, first revealed news of his granddaughter's birth Tuesday while speaking at Variety's Dealmakers Breakfast in Beverly Hills, California.

"My daughter had a baby last night," he said while sitting down with Claudia Eller, Variety's chief production officer. "I left the hospital at 1:30 and got there this morning at 6. I'm a little tired, but happy."

"Everything's great," he added. "So if I wander, it's because the adrenaline is still flowing."

Lourd first revealed her baby bump in September at the London premiere of Ticket to Paradise, posing with her hands on her belly alongside Rydell.

RELATED: Pregnant Billie Lourd Wishes Mom Carrie Fisher Filmed While Expecting: 'Would've Been Incredible'

Gilbert Flores/Getty

Speaking with PEOPLE in October at the Los Angeles premiere of Ticket to Paradise, Lourd discussed how different her second pregnancy had been from her first during the COVID-19 pandemic.

"I went nowhere," she said. "I knitted a blanket, and I watched The Sopranos, and I watched The Wire and I didn't leave my couch. It was a very different vibe."

This time, not only was Lourd managing a toddler, but she continued working throughout her pregnancy. She jokingly called herself "a psycho person" as she reflected on her busy last few months.

"I did American Horror Story, and then I just wrapped this other movie that I shot in London," she said.