Grace Gummer and Mark Ronson are expanding their band.

The couple—who tied the knot in 2021—debuted Grace’s growing baby bump at pal Justin Theroux’s annual holiday party at Pebble Bar Dec. 18.

For the occasion, Grace, whose parents are Meryl Streep and Don Gummer, donned a form-fitting, short-sleeved red dress which she styled with subtle gold jewelry and a black handbag—letting her pregnant belly do all the talking.

Mark, meanwhile, wore a simple white and blue pinstriped button down while his left arm was cradled in a sling.

Grace, 38, and 49-year-old Mark’s happy news comes almost two years after they welcomed a baby girl, whose name they’ve kept private, in early 2023. In March, Mark’s sister Annabelle Dexter-Jones told People of her niece, “She's two and a half months now. She's stunning.”

When it came to her first pregnancy, Grace shared the news in a very similar fashion to that of her second pregnancy.

Rather than make an official announcement, she showed up to W Magazine's 50th-anniversary party in October 2022 in a form-fitting red sweater dress, her baby bump on display. She finished off the monochrome look in a matching red coat and strappy heels.

The couple are notoriously private, keeping much of the details of their personal lives to themselves. In fact, when it came to getting married, the pair—who had each previously been married, Grace to Tay Strathairn and Mark to Joséphine de La Baume—kept the news close to the chest.

In fact, while it was reported that they’d married in an August ceremony in New York City in 2021, it wasn’t until one month later that Mark confirmed the happy news with a sweet tribute to his wife.

"To my truest love...out of nowhere, you made 45 hands down the greatest year of my life," the music mogul wrote on Instagram in Sept. 2021, alongside a romantic portrait of their big day. "And i'm sure it took me 45 years to become the man worthy of your love. I hope I spend every one of these birthdays by your side til my last day. And beyond."

And to make everything crystal clear, he added, "(and yes, we got married)."

But while Grace and Mark prepare for welcoming their little one, keep reading for more celebrity families that have expanded this year.

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).

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."

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.

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."

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.

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." 

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."

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.

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.

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.

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!"

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."

Clint Eastwood became a grandpa again when his daughter gave birth to a baby girl named Cleo in September.

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. 

The Bachelor Nation star and his husband found baby bliss when they welcomed son Bishop Colton Brown-Underwood on Sept. 30. 

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."

The England national team soccer star and his partner welcomed a new teammate—a baby girl named Mila Rose Grealish—on Sept. 27.

The daughter of Kurt Cobain and the son of Tony Hawk welcomed a baby boy named Ronin Walker Cobain Hawkon Sept. 17.

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."

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."

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.

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."

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.

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."

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. 

The Glee alum gave birth to her second child—a daughter named Emery Sol Reich—with the entrepreneur, writing on Instagram Aug. 25: "Our hearts are so full." She's also mom to son Ever.

Meet the new Princess of Malibu! The reality star and his wife welcomed daughter Joan Almond Jenner in August."Born at home in a flash, just the most amazing experience for mama and baby girl," Brandon—who is also dad to twin sons Bo and Sam as well as  daughter Eva with ex Leah James—wrote on Instagram. "A beautiful, gentle birth. 9 lbs 2 oz, 21 1/2 inches long."

The Parenthood alum announced her journey into motherhood on Aug. 28, revealing that shenamed her baby boy after her former costar Miles Heizer.

It's a baby, baby, baby, oh! The pop superstar and the Rhode skincare founder shared on Aug. 23 that they welcomed son Jack Blues Bieber.

The country star welcomed a new gold chain cowboy when his wifegave birth sonMajor Yancey Tyler McCollum onAug. 8.

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