The supermodel, 42, shared the exciting baby news on Instagram, captioning a photo: "WHEN 3 BECOMES 4 ❤️❤️❤️❤️ Our darling little bun came out of the oven earlier this week 🍞 Sweet little soul. You are already so blessed. Healthy as can be with a family that has fallen head over heels in love with you. A big brother that is already so attentive and protective, (who has also handled all these big changes like a boss ) a Dad who is so smitten with you and that you already have firmly wrapped around your little finger. And myself, who's been so lucky to have carried you in my belly for 9 months and to have had the pleasure and privilege of birthing you into this world (and can I just say .. we nailed it kid 👊🏼). I'm so committed to being the absolute best mother, friend and role model for you. Thank you for choosing me to be your Mama, my darling girl."
Gale and her fiancé Shaun Hampson, 29, are already parents to son River, three.
Speaking to WHO in May last year, Gale opened up about being a mum-of-two.
"I'm not really that overwhelmed by it. I'm sure it will take the whole juggling act to the next level but I'm really excited to expand on my family," Gale said.
"We're really enjoying these last months that we have with River just the three of us. But I'm just looking forward to all the memories we'll create as a family of four."