Mallette’s comment came after fans speculated over her use of the word “grand-babies” on Stephen Baldwin’s Instagram post

LOS ANGELES, CALIFORNIA - JANUARY 27: Pattie Mallette, Justin Bieber and Hailey Bieber arrives at the Premiere Of YouTube Originals' "Justin Bieber: Seasons" at Regency Bruin Theatre on January 27, 2020 in Los Angeles, California.

Pattie Mallette, Justin Bieber and Hailey Bieber arrive at the 2020 Premiere Of YouTube Originals’ “Justin Bieber: Seasons” . PHOTO: STEVE GRANITZ/WIREIMAGE

Justin Bieber’s mom Patti Mallette is giving fans an update about Hailey Bieber’s pregnancy.

On Thursday, May 9, the Biebers announced they are expecting a baby together in a sweet joint Instagram post showing footage of the couple — who have been married since 2018 — during a vow renewal ceremony.

A rep for Hailey, 27, confirmed to PEOPLE shortly after that the model is just over six months pregnant. And later the same day, Mallette, 49, — who had already shared her delight at the news in a Reel posted on Instagram — revealed to fans that the couple definitely isn’t expecting twins.

Commenting on a post from Hailey’s father, Stephen Baldwin, where the actor celebrated his daughter’s happy news, Mallette first wrote: “Congratulations Grandpa! WE ARE GONNA HAVE THE CUTEST GRAND-BABIES EVER!”

Mandatory Credit: Photo by Diggzy/Shutterstock (14148766a) Justin Bieber and Hailey Bieber were all smiles as they stepped out for a date night to support Victoria Monet in LA on Thursday. The adorable duo wore matching leather jackets as they posed backstage before joining Tori Kelly and Other Celebrity guests to watch the show. Justin and Hailey Bieber Match in Leather Jackets as They Join Tori Kelly to Support Victoria Monet at The 2nd Night of Her Sold Out Jaguar Tour, Los Angeles, USA - 12 Oct 2023

Justin and Hailey Bieber match in leather jackets on a 2023 date night.DIGGZY/SHUTTERSTOCK

However, her use of the phrase “grand-babies” had fans wondering whether Hailey and Justin, 30, were expecting two mini-Biebers.

“@pattiemallette is there more than one baby twins,” one user wrote in response, while another commented, “@pattiemallette wait, babies????”

The fan speculation led the “Baby” singer’s mom to add a further comment on Baldwin’s post, writing, “No not twins lol I wish. I just mean in general. Hopefully they will have more than one eventually. They will make beautiful babies whenever they have them. One is enough for now 😂.”

On May 9 a source told PEOPLE that the Biebers are already decorating their nursery and have chosen a name.

“Everyone is excited for them,” the source revealed. “They will be great parents, and Justin will be super involved. This will be the next important project for him. He’s so excited to raise his baby. They have a name that they think is perfect. They’re also starting to decorate a nursery. They can’t wait to meet the baby.”

The couple’s sweet baby reveal video showed Hailey wearing a Saint Laurent by Anthony Vaccarello white lace dress which gave fans a glimpse at her growing baby bump. She teamed the stunning gown with black Saint Laurent sunglasses and a bespoke lace head scarf that also served as a veil.

Justin Bieber and Hailey Bieber attend OBB Media's Grand Opening of OBB Studios

Justin Bieber and Hailey Bieber at the 2023 Grand Opening of OBB Studios.JERRITT CLARK/GETTY IMAGES

Friends, family and fans have been quick to share their excitement at the news, with Hailey’s uncle Billy Baldwin telling PEOPLE at the Americans With No Address VIP Screening in Los Angeles on May 9 that he is “excited” about his niece and nephew-in-law’s growing family.

“I just found out a couple of hours ago,” Baldwin told PEOPLE at the event.

“My niece and nephew [were asking], ‘Have you talked to Stephen [Baldwin] yet? Been able’ — No, I haven’t. I just texted him,” he revealed, adding, “But this will be his second [grandchild] and I’m excited.”