Karlie Kloss and her husband Joshua Kushner have welcomed their first child

Supermodel Karlie Kloss and her businessman husband Joshua Kushner have welcomed their first child together.

Josh took to social media to express their baby joy on Sunday, sharing a photo of the newborn.

'Welcome to the world,' Josh wrote beside the snap.

Karlie and Josh are yet to reveal the baby's name or if they are a boy or a girl, but the photo of the tot in a blue hat may well be a hint.

Messages from the famous couple's celebrity friends flooded in after the birth announcement was made public.

Kate Hudson congratulated the new mum with a string of heart emojis, which were shortly followed by model Gisele's sweet advice, which read, 'Congrats !!! Enjoy every moment. They grow so fast!'

The first-time parents revealed they were expecting their first child in November when Karlie posted a video on Instagram of her growing baby bump which she captioned, 'Good morning baby.'

Karlie and Joshua had just celebrated their second wedding anniversary before the exciting announcement.

Meanwhile, at the end of December, Karlie told WSJ Magazine that her pregnancy cravings were "salty and crunchy" snacks.

She added, "I’ve always had bizarre cravings, so it’s kind of nothing new, but I’ve really been loving everything salty and crunchy."

Karlie shared that she's always kept active before she became pregnant and since then nothing has really changed-except her stamina level.

She told the magazine, "I normally love running but I have to say I'm out of breath these days just talking or going up a flight of stairs"

"Being pregnant has put a little bit of a damper on my running routine but I still have been trying to stay active no matter what, going for lots of long walks."

Karlie added that she was looking forward to some 'new mom groups' and was excited for all of her friends who were "entering this next chapter of life."