Grant Gustin is starting his greatest role yet: father of two.
The former The Flash actor and his wife, LA Thoma announced the arrival of their son, Arthur James Grant, in a joint Instagram post on Sept. 12.
"Juni's best friend is finally here," they captioned a black-and-white photo of their newborn holding one of their hands, referencing their 3-year-old daughter, Juniper.
Grant, 34, commented on the post, too, gushing, "Love this little family beyond words."
The couple, who tied the knot in 2018, had previously announced that they were expecting another child with a March 3 Instagram post.
In the adorable reveal, LA, 35, wrote that it was "shaping up to be an exciting year" along with a black-and-white mirror selfie showing off her burgeoning baby bump. Meanwhile, Grant could be seen hugging her from behind as Juniper—wearing a shirt that adorably said "in my big sister era" on the back—grabbed his leg.
As the physical therapist added on her Instagram Story at the time, "Now you know why I retreated to my cave for the last couple months."
The arrival of the couple's first son together comes less than two weeks after another milestone—Grant's final performance as the male lead in the Tony-nominated Broadway musical, Water For Elephants. The final show of his Broadway debut was on Sept. 1.
Last year, Grant experienced another major change in his life when he said goodbye to The Flash, which came to the end after nine seasons.
"I'm ready for it to be over," the actor, who played Barry Allen, told E! News in March 2023 ahead of the CW show's final season. "And that's not for any negative reason. It's like when you're getting ready to finish high school and—granted I don't know what college I'm going to after this, I might not get into college—but you're excited to wrap up and move on to the next phase of your life."
Grant added at the time, "I'm ready emotionally and my family is ready to just kind of move into the next chapter together."
Keep reading for more celebrity baby arrivals from 2024.
Sophia Grace Brownlee
The former Ellen DeGeneres Show correspondent gave birth to her second child, a baby girl named Athena Rose, on Dec. 29.
Gypsy Rose Blanchard & Ken Urker
The Gypsy Rose: Life After Lockup star and her partner welcomed their first child, a baby girl named Aurora Urker, on Dec. 28.
Andi Dorfman & Blaine Hart
The Bachelorette alum and her husband welcomed baby girl Harper Bell Hart on Dec. 20, but Andi was hospitalized days later to undergo surgery for remove hematomas.
"Welp, we're back! This time for Mama," she quipped on Instagram Stories Dec. 27. "After getting home, I was in a ton of pain and it was getting worse by the day. Despite the internet saying recovery takes time, I still felt something was wrong and finally after trying every home remedy, called my doctors and they told me to come right in."
She added, "A very straightforward procedure but still pretty terrifying having a 6 day old baby (plus loads of hormones still lurking)."
Scarlet Vas & Tayo Ricci
The OnlyFans model gave birth a baby girl with her husband—who is also her stepbrother—in December.
"Our Christmas miracle has finally arrived," Tayo wrote alongside a Dec. 25 Instagram post featuring a photo of the pair cradling their newborn, as well as a snap of them holding their baby's hand. "Merry Christmas from our family to yours."
Madeline Gaudreau & Matthew Gaudreau
Madeline—the widow of the late hockey player—gave birth to the couple's first child in December, four months after Matthew was fatally struck by a car while riding his bike with his brother, NHL star Johnny Gaudreau. She named their baby boy Tripp Matthew Gaudreau.
Lindsay Hubbard
The Summer House star announced Dec. 8 that she gave birth to her first baby, daughter Gemma Britt Kufe, with her boyfriend (whom she has not identified).
Jenna Ushkowitz & David Stanley
The Glee alum announced the arrival of her and her husband's second baby—a son named Graham—on Nov. 24.
"And then they were 4," Jenna, who is also mom to daughter Emma, wrote on Instagram. "Welcome to the tribe, Graham, we love you so much."
Francesca Farago & Jesse Sullivan
On Nov. 11, the Perfect Match alum gave birth to twins Poetry and Locket—her first children with her fiancé. TikToker Jesse also has a teen, Arlo, from a previous relationship.
Desiree Hartsock & Chris Siegfried
The former Bachelorette made a rosy announcement when she shared she welcomed baby No. 3, son Noah Parker, with her husband Nov. 5.
"We're doing well & getting adjusted to a family of 5," Desiree, who is also mom to sons Asher and Zander, wrote on Instagram a week later. "He's just as sweet as can be!! And looks just like his brothers."
Chris Pratt & Katherine Schwarzenegger
The Guardians of the Galaxy star and his wife became guardians to a baby boy named Ford Fitzgerald Schwarzenegger Pratt on Nov. 8. Their little one joined big sisters Lyla and Eloise, as well as Chris’ son Jack with ex-wife Anna Faris.
Campbell "Pookie" Puckett & Jett Puckett
The TikTokers welcomed a baby girl named Paloma Campbell Puckett in November 2024.
"My angel has given me another angel," Jett quipped while announcing his daughter's arrival. "Daddy's got two angels. Pookie and mini Pookie."
Alexandra Daddario & Andrew Form
The White Lotus alum's little one checked into the world on Halloween. To announce the news, Alexandra posted a photo to Instagram of her and her husband's newborn at the hospital and joked, "I thought this was a weird bowl of candy."
Candiace Dillard Bassett & Chris Bassett
The Real Housewives of Potomac alum and her husband welcomed their first baby together, son Jett Maxwell Lee Bassett,on Oct. 3, the couple confirmed to People. As the outlet noted, the bundle of joy joins Chris' kids Owen, Mateo and Naia from previous relationships.
Whitney Leavitt & Connor Leavitt
The Secret Lives of Mormon Wives star and her husband welcomed baby No. 3, son Billy Gene Leavitt, in October 2024.
On the Hulu show, fans saw Whitney announce her pregnancy by hiding a positive pregnancy test in a cake that she gave to her family.
"We all definitely ate the cake," she told The Cut in September. "Look, I put the lid back on it. I Cloroxed the heck out of it before putting it in the cake. It was clean. I get how people were like, Ew. Maybe people tried to stay away and not eat the pieces surrounding the test, but that cake was good."
Whitney and Connor are also parents to kids Liam and Sedona.
Margot Robbie & Tom Ackerley
This Barbie became a mom when she and her husband welcomed their first child in the fall. According to People, Margot gave birth to a baby boy.
Carli Lloyd & Brian Hollins
The former soccer player and the pro-golfer shared they welcomed their first baby, a girl named Harper, Oct. 18.
"So very grateful for this amazing blessing in our lives," Carli wrote on Instagram Oct. 21. "By far the hardest thing I have ever endured but the best thing I’ve ever done!"
Brantley Gilbert & Amber Cochran Gilbert
The country music singer and his wife became parents to three after she gave birth to Abram Howell Gilbert on a tour bus Oct. 11.
"We will never forget the way you got here," Brantley, who is also dad to kids Barrett and Braylen, wrote on Instagram two days later, "we can’t wait to see what you do here."
Morgan Eastwood & Tanner Koopmans
Clint Eastwood became a grandpa again when his daughter gave birth to a baby girl named Cleo in September.
Pauline Chalamet
The Sex Lives of College girls actress officially enrolled in mom life, announcing on Sept. 30 that she gave birth to her first child "three weeks ago."
Pauline, who is the sister of Timothée Chalamet, has not publicly disclosed the identity of her baby's father.
Colton Underwood & Jordan C. Brown
The Bachelor Nation star and his husband found baby bliss when they welcomed son Bishop Colton Brown-Underwood on Sept. 30.
Nina Agdal & Logan Paul
After the model gave birth to her and the YouTuber's first baby, she wrote on Instagram Sept. 29, "Esmé Agdal Paul has entered the chat."
Jack Grealish & Sasha Attwood
The England national team soccer star and his partner welcomed a new teammate—a baby girl named Mila Rose Grealish—on Sept. 27.
Frances Bean Cobain & Riley Hawk
The daughter of Kurt Cobain and the son of Tony Hawk welcomed a baby boy named Ronin Walker Cobain Hawk on Sept. 17.
Mandy Moore & Taylor Goldsmith
The This Is Us alum found herself with a Big Three of her own in September, when she and her musician husband welcomed daughter Louise Everett Goldsmith.
The baby girl joins older brothers August "Gus" Harrison and Oscar "Ozzie" Bennett.
"Lou is here!" Mandy wrote on Instagram Sept. 25. "Louise Everett Goldsmith arrived happy, healthy, expeditiously and right in time for Virgo season. She is our absolute dream girl and her big brothers are already as obsessed with her as we are. Endlessly grateful for our family of 5 (and our very own big three) and soaking in every moment of this special time."
John Mulaney & Olivia Munn
Everybody's in LA—including the couple's daughter Méi June Mulaney, whom the comedian and the actress welcomed via surrogate on Sept. 14.
"I am so proud of my little plum," Olivia—who also shares son Malcolm Hiep Mulaney with John—wrote on Instagram, explaining that her baby girl's name (pronounced May) is the Chinese word for plum. "My heart has exploded."
Jamie Otis & Doug Hehner
The Married at First Sight couple doubled their brood's size on Sept. 18, welcoming twin boys Hawkins Tyler Hehner—born 6:05 p.m.—and Huxley James Hehner, who arrived three minutes later.
"Baby A was born normally. I pushed him out so fast, baby B was born BREECH," Jamie later wrote on Instagram. "It was a scary moment at first bc he was quite stunned and didn’t cry immediately but when he finally kinda 'came to' & I heard his little squeal I just lost it."
Jamie and Doug are also parents to Henley Grace Hehner and Hendrix Douglas Hehner, and every year mark the "angelversary" of Johnathan Edward.
Grant Gustin & LA Thoma
The Flash alum and his physical therapist wife announced the birth of their son Arthur James Grant on Sept. 12, calling the baby boy their older daughter Juniper's new "best friend."
Cardi B & Offset
More than a month after filing for divorce, the "WAP" rapper gave birth to her third child with the Migos member Sept. 7. The former couple's older kids—daughter Kulture and son Wave—visited their new sibling in the hospital. Offset is also dad to kids Jordan, Kody and Kalea from previous relationships.
Ashley Tisdale & Christopher French
The High School Musical alum and her composer husband welcomed their second child, Emerson Clover French, Sept. 6. As Ashley, who is also mom to daughter Jupiter, wrote in an Instagram message to her baby girl, "All three of us are obsessed with you."
Lala Kent
The Vanderpump Rules star became a mom of two on Sept. 3, when she gave birth to daughter Sosa—whom she concieved through the use of a sperm donor and intrauterine insemination (IUI).
The baby girl's arrival came three years after Lala's breakup with Randall Emmett, with whom she shares older daughter Ocean.