Hilary Duff hosted a music class for the babies of her famous friends

Hilary shared some photos from the class - which also included food blogger Gaby Dalkin and her six-month-old daughter Poppy, and make-up artist Kelsey Deenihan Fisher and her four-month-old baby, who is also named Poppy - on her Instagram story on Sunday (18.07.21), and some of the other famous moms followed suit.

'This Is Us' actress Mandy shared a photo of the babies lying together on her Instagram Story and wrote: "Music class! Thanks for giving us a reason to get together!"

And Ashley posted photos of the infants lying together in a row.

She captioned the post: "Cutest class! Thanks @HilaryDuff for hosting (sic)"

She also shared pictures of Jupiter lying on her back, and with the tot's mouth open in one photo, she wrote: "Trying to sing."

The 'High School Musical' star found one of Hilary's photos particularly amusing.

The 'Lizzie McGuire' actress had shared one picture of Jupiter and Mae lying next to one another and observed: "Juju has that strong side eye."

Ashley reposted the image with some laughter stickers and wrote: "She sure does."

Hilary recently admitted her two older children, nine-year-old Luca and two-year-old Banks - who she has with ex-husband Mike Comrie and second spouse Matthew respectively - have embraced having a new sibling.

She said: "You know what, since Luca went through it with Banks, he just knows what to expect and was the best. He was super excited to have another sibling and he was annoyed that we weren’t finding out the gender. He really wanted to know the gender. But you know, he’s like, ‘Okay, I’m, uh, I have sisters’ and he loves babies.

"[Banks is] unphased and she’s really loving. She wakes up first thing in the morning and I go to get her out of her crib and she’s like, ‘I’m going to pet Mae Mae’. I’m like, ‘Oh, okay. You can go pet her.’ I think she thinks she’s like her little dog.”