Kelly Osbourne shared a rare glimpse of her blossoming baby bump on Friday evening during her mom's extravagant 1920s-themed birthday party.MORE: Kelly Osbourne addresses 'cutting comments' about Sharon and Ozzy's marriageThe mum-to-be, 37, marked the special occasion in a stunning lilac maxi dress which she teamed with a pearl-encrusted headband and opulent pearl accessories.WATCH: Sharon and Ozzy Osbourne's Wild Love StoryKelly elevated her Gatsby-inspired outfit with a touch of striking makeup in the form of mauve lipstick and smokey eyeliner.In keeping with the theme, the pregnant star styled her pastel purple tresses in loose curls for an effortlessly glamorous look.MORE: Kelly Osbourne reveals surprising change at family home since becoming pregnant with her first childMORE: Ozzy Osbourne 'breaks Sharon's heart' with health update after life-altering surgeryReflecting on the family celebration, Sharon shared a series of photos on social media. Taking to Instagram, the 70-year-old posted a carousel of family photos alongside the touching caption: "All my wishes in one room.