Hailey Bieber has become an aunt for the first time, after her sister Alaia Baldwin gave birth.

Alaia, 27 - the eldest daughter of actor Stephen Baldwin - welcomed a daughter, Iris, into the world on Monday (17.08.20), and she and her little one are ''happy and healthy''.

She wrote on Instagram: ''IRIS ELLE ARONOW!Born on 8/17/2020, 6lbs 11oz. She is absolutely perfect, we are all happy and healthy. Thank you so much @drthaisaliabadi for making our experience go as smoothly and as beautifully as I ever could have imagined. We love you! (sic)''

Hailey responded: ''My perfect baby girl and her BAD A** warrior mommy (sic)''

Following the announcement, Hailey - who is married to Justin Bieber - also took to her Instagram Stories to admit it had been tough keeping the news a secret this week.

She wrote: ''been hard to keep this to myself, my beautiful niece is here and she is perfect.

''Auntie Hails loves you soooo much (sic)''

Alaia announced in April that she and her husband Andrew Aronow were expecting a child together, and she shared a picture of him kissing her baby bump.

She wrote alongside the image: ''I made something extra special for @andrewaronow's birthday this year..... #BABYARONOW coming to ya August 2020 #it'sagirl #happybirthday and #yourewelcome (sic)''

Hailey couldn't contain her excitement as she took to the comments to express her joy at becoming an aunt.

She wrote: ''My niece

''Screaming!!!! (sic)''

Hailey also shared Alaia's post on her own Instagram Story, where she wrote: ''I'm gonna be an Aunty!!!!!! (sic)''