Luke Hemmings and Sierra Deaton made their sweetest collaboration to date.

The 5 Seconds of Summer singer and his wife announced that they privately welcomed their first child, a baby girl.

“Our best kept secret,” Luke and Sierra shared in an Aug. 22 joint Instagram post that included photos of their baby’s feet and hands, Sierra showing off her baby bump during a floral-themed maternity shoot and a video of Luke kissing his wife’s stomach. “Written and Produced by Sierra and Luke Hemmings.”

Luke, 29, and Sierra, 34, did not share any further details including their baby’s name or birthday. However, the “She Looks So Perfect” singer revealed why they decided to get ahead of the news.

“In our perfect world, we’d keep our daughter a secret forever…for similar reasons we chose to never share our wedding photos from years ago,” Luke wrote in the comments. “However, going into this next album cycle I’m very aware that her existence would inevitably leak. To avoid any speculation, we’re posting this now and humbly asking for everyone to respect her privacy.”

Luke also asked fans to respect specific boundaries.

“If you see us in public, please avoid taking or sharing photos of her as we don’t plan on publicizing her name, birthdate or face anytime in the near future,” he wrote. “Thank you for understanding and for the support. All our love, the Hemmings.”

Luke and Sierra have kept the details of their romance largely private since it began in 2018. In 2021, the “Youngblood” singer revealed that he proposed to his longtime love.

“With shaking hands but a full heart I proposed to my best friend earlier this year,” he wrote June 2021 alongside a photo of Sierra showing off her sparkler while holding his face. “I love you Thao and I can’t imagine my life without you @sierradeaton.”

Luke revealed that him and Sierra quietly tied the knot almost three years later. When complimented on his eye makeup during his appearance alongside his band, Luke spilled the beans.

“Thank you! My wife did it,” he told Entertainment Tonight in an interview alongside bandmates Michael Clifford, Calum Hood and Ashton Irwin at the time. “Usually I do it for stage but she’s taught me well and she did it tonight. It’s a big event so she did it.”

When asked about married life, Luke coyly replied, “It’s very good. I love it.”

For more stars who welcomed babies in 2025, keep reading…

The Stranger Things star and son of Jon Bon Jovi revealed they welcomed their first baby one year after getting married.

"This summer, we welcomed our sweet baby girl through adoption," the couple wrote in an Aug. 21 Instagram post. "We are beyond excited to embark on this beautiful next chapter of parenthood in both peace and privacy."

They concluded, "And then there were 3."

on Aug. 6, the Outlander alum announced that she gave birth to her and her producer husband's first baby, a daughter. 

In August, the Dawson's Creek alum confirmed she is now the mom to "three under 5," with husband Thomas Kail on top of her teenager Matilda she shares with the late Heath Ledger. 

"This last baby did not come through my body," Michelle joked of welcoming her latest bundle of joy via surrogate during an appearance on Jimmy Kimmel Live! "but the miracle of our little girl is thanks to Christine."

The DJ and the British radio personality welcomed their first babytogether, a boy named Micah, on July 20.

"My wife is a superhero and I am in complete awe of her primal wisdom," Calvin wrote on Instagram Aug. 4. "Just so grateful. We love you so much Micah."

The influencer and the rapper welcomed their first baby together, a girl named Eloísa, on July 26. 

The YouTuber announced that she and her husbandwelcomed their third and "final" baby on July 12.

She also unveiled their son's super powerful name—Aquaman Moses Paytas-Hacmon—by revealing a bedazzled T-shirt of the DC comic book character.

The NCIS star and his fiancée welcomed their second child, a baby boy, who joined his big sister Nakano Oceana.

“Wolf Monte Valderrama,” the pair wrote on Instagram July 20. “7/11/2025.”

The Secret Lives of Mormon Wives star gave birth to her third child, a baby girl named Penelope, after going into labor at her nail appointment in July.  

“Baby Penelope is here,” Jen—who also shares Nora and Lucas with husband Zac Affleck— captioned her Instagram post on July 2. “She is perfect.”

The retired NFL quarterback and former Miss Universe shared that they welcomed their first baby, a little girl, on July 6, writing on Instagram, "We couldn’t be more grateful for the blessing and gift of this new little life."

The Real Housewives of Atlanta alum—who shares Aaron “Deuce” and Asani with Aaron— announced July 2 that she had welcomed her and the former NFL player’s third baby boy. 

The Southern Charm star and her husband welcomed their first child together, a daughter named Teddi—in honor of Madison’s father Ted LeCroy—in June. 

The exciting news came after the Madison—who shares son Hudson with ex John Hughes—announced her pregnancy in a smiling Feb. 6 Instagram photo.

“Obviously, the main thing is just a healthy baby overall, girl or boy,” Madison told E! News in February. “I have a feeling that I’m gonna have to make sure that Brett gets both, but he’s happy either way. We all know that I’m already a boy mom, so of course I wanted to be a girl mom as well.”

At 17 years old, the American Idol alum became a dad in June when he and his wife welcomed daughter Brenley Lichelle Harper.

The Below Deck Mediterranean stars welcomed their first child together, proudly announcing their baby boy’s arrival in a June 24 Instagram post simply captioned, “Welcome to the world, my love.”

The couple shared they were expecting in April. “The moments our hearts grew even bigger…Our little boy,” Gael captioned the reveal. “We can’t wait to share our world, our laughter, and all of life’s wild adventures with you. Our greatest journey yet is just beginning.”

The “Twinnem” rapper welcomed her first child, a baby girl, with ex Trippie Redd. Coi shared the news with a glimpse of her daughter on her Instagram story June 16.

The Sports Illlustrated Swimsuit model and the MLB star welcomed baby No. 2—a boy named Bellamy Brooks Verlander—in June.

The pair are also parents to daughter Genevieve.

The Valley stars welcomed their fourth baby a daughter named Adelaide, on June 5. The pair announced their daughter’s birth with an Instagram carousel of pictures and videos of their newest addition.

“Sweet little memories from Adelaide’s first moments of life,” Nia captioned her Instagram post. “We are absolutely in love!”

The Teen Mom star welcomed twin girls with her fiancé on June 2, one year after their engagement.

The American Idol alum shared she and husband welcomed their first baby, a girl named Beni,on June 11.

The Vanderpump Rules star expressed feeling “lucky” after welcoming baby Kaia Lily with her fiancé in June. 

The “Long Way 2 Go” singer gave birth to a baby boy on May 27, her third baby with husband Alex Fine.

The news of the couple’s newest arrival came three months after they announced her pregnancy on Instagram on February 19. Cassie posted a carousel of family photos with her and Alex’s daughters Frankie and Sunny alongside the caption “#3.”

The “Body Like A Back Road” singer and his wife, Hannah Lee Fowler, welcomed their third baby, a son named Wayman Allen Hunt on May 21.

The couple are also parents to Lucy Louise and Lowry Lee.

The Little Mix alum and her boyfriend Zion Foster welcomed identical twin girls, Ocean Jade and Story Monroe in May.

“So…Our beautiful baby girls decided to come at 31 weeks plus 5 days,” Jesy captioned an Instagram post of her and Zion with their baby girls. “It all happened so quickly, but we are so blessed that they are here with us, healthy and fighting strong! We’ve never felt more in love.”

The Aquaman actress announced on Instagram May 11, Mother's Day 2025, that she has welcomed twins, daughter Agnes and son Ocean, who join big sister Oonagh.

Jimmy Kimmel announced during the May 20 episode of his late night show that his daughter Katie Kimmel and her husband Will Logsdon welcomed a baby girl, Patti Joan. 

The Hills alum and his wife welcomed their third child together on May 8, adding a baby boy named August to their familiy. 

The Love Is Blind alum welcomed her second child with boyfriend Cameron Shelton, a baby boy named Cason Wayne Shelton in April.

“We couldn’t be more in love,” Taylor captioned an Instagram carousel featuring the couple’s new addition.  “1/2 of me and 1/2 of the person I love most.”

The Ultimatum couple welcomed their third baby, named Royce Canon Kissinger, in April.

The Los Angeles Dodgers star player announced April 19 that his wife had given birth to their first baby, a girl.

While still legally married to Gino Palazzolo, the 90 Day Fiancé star gave birth to a baby girl named Matty with her boyfriend, she announced in April.

The Love Is Blind couple, who appeared on season one of the Netflix dating series, announced April 6 that they have welcomed their first baby, a daughter.

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