Kristin Cavallari has adopted a German Shepherd cross puppy.

The former 'Hills' star, 28, already has her hands full with sons Camden, two, and 10-month-old Jaxon, whom she has with husband Jay Cutler, but has now added a pet pooch to her brood.

Taking to her Instagram account over the weekend, the blonde beauty shared an adorable photograph of her new four-legged friend gazing at the camera while sitting outside.

She accompanied it with the sarcastic caption: ''Because 2 boys under the age of 3 weren't enough (sic).''

Meanwhile, the jewellery designer admits motherhood is hard work but she's hoping to have another baby in the near future.

She said recently: ''We love having kids, so I do think we'll end up having another one but then we're done.''

She added: ''Being pregnant for a full nine months isn't the best thing in the world.''

Kristin sprung back into shape after giving birth to Jaxon but she's now worried she's too thin and is trying to bulk up.

She said: ''I don't know why or how but after I had children my body literally changed and now, for me, it's about trying to keep muscle on so I don't look too thin.

''Because it's very easy, especially because I have no curves, that I can look really skinny and I don't like that look.''