Kristin Cavallari's husband threw her a surprise party to mark her 30th birthday.

Kristin Cavallari

Kristin Cavallari

The 'Hills' star gushed about her husband Jay Cutler - with whom she shares Camden, four, Jaxon, two, and Saylor, 13 months - as she posted a sweet picture of the pair kissing on social media.

Captioning a picture of herself and Jay, she wrote: "This is the only somewhat decent picture I have from last night (and we're both clearly sober) but Jay really went all out for my 30th birthday.

"He threw the most amazing surprise party and made me feel so special and loved and I will forever be grateful for this man, my family, and all my amazing friends. I am the luckiest girl in the world to have such incredible people in my life."

Meanwhile, Kristin previously opened up about how therapy saved her relationship with the 33-year-old American football star.

She explained: "I think it's important for people to know that there's no such thing as a perfect relationship, you know? We work on it. It's true. We love each other and we want to make it work, but I 100 per cent credit our therapist for saving our relationship. We've come so far being in therapy both individually and together as a couple, that it's been incredibly beneficial.

"We moved very quickly: We got engaged after eight months, and then we actually broke up about two and a half, three months later. Called off the engagement. And then we got back together, and when we got back together, I kind of went through a little phase where I didn't know if I wanted to get married. I think it was really more about my ego, I had one foot in and one foot out and that was ridiculous. And if we were gonna be together and really give it a shot, that wasn't fair. So, I decided to grow up, I guess."