The plus-size model welcomed her son on Monday, confirming the news to People magazine.
The baby boy is the first child for 30-year-old Tess and her fiancé Nick Holliday, although the size 22 model already has a 10-year-old son, Rylee, from a previous relationship.
The couple have chosen a rock star name for their little one, opting for Bowie Juniper Holliday. At the time of his birth, Bowie weighed 8lbs, 10oz. and measured 22 inches long.
The pair have been quick to share pictures of their new arrival on their social media accounts. Nick took to Instagram to share this sweet black and white snap of him holding Bowie, with the caption:
'Cats outta the bag! Meet my little guy, Bowie Juniper Holliday.'
New mum Tess, who publicly confirmed her pregnancy in January, has been outspoken about her thoughts on body confidence throughout her pregnancy, sharing lots of photos of her growing baby bump as well as nude pics celebrating her changing figure.
Tess appearing on Lorraine in September last year
The model has fought off criticism from social media users who have insisted that she was risking her baby's health because of her size. She posted this revealing snap three weeks ago, showing her growing baby bump and hitting back at critics, writing:
'When people say to me "I can't tell you're pregnant" & my face is like😏😂 I will continue to live unapologetically, to thrive in this body, prove the naysayers wrong & laugh at the ignorance #babyhollidayontheway #37weeks #effyourbeautystandards #plussizepregnancy'
The couple threw a tropical-themed baby shower for friends and family in May, with Tess showing off her blossoming baby bump at the time. Just two weeks ago the model shared a pic of her enjoying the Memorial Day weekend by posting a snap of her resting a cup on her bump, captioning the fun pic: 'Showing off my #babybump skills 😂'
Congratulations to the new parents!