Miley Cyrus' ex Kaitlynn Carter is a first-time mother.

The Hills: New Beginnings star and her boyfriend Kristopher Brock welcomed a baby boy named Rowan Carter Brock into the world last month.

The newborn weighed a healthy 8 lbs 4 oz and arrived in the early hours of 30 September.

Alongside a snap of the new mom breastfeeding the tot, Kaitlynn announced on Instagram: "Our chunky little guy, Rowan Carter Brock, was born 9/30/21 at 2:53am, 8 lbs 4 oz. everyone is happy and healthy and so in love. (sic)"

Kaitlynn revealed her pregnancy in June as she shared a silhouette that depicted her and Kristopher holding hands, while her baby bump was on full display.

Kaitlynn's baby news came just over a year after she began dating Kristopher following her split from Miley, whom she romanced just after her separation with ex-husband Brody Jenner.