The couple met working together on `The Last Song` in 2009 and though the actor admitted he wanted to be professional on the film, they couldn`t help but fall in love after working so closely together.
He said: "What happened happened, and we`ve been together two and a half years.
"She makes me really happy. When you start, you want to be professional, but when you`re filming those scenes with someone and pretending to love them, you`re not human if you don`t feel something."
Liam gets on well with Miley`s family, particularly her father, country singer Billy Ray Cyrus, and he is particularly pleased to have been introduced to some local Nashville delicacies by the clan.
He told Details magazine: "Billy Ray is very spiritual. He`s just one of the nicest guys. Very accommodating. I`ve listened to his music since we got together. It`s awesome...
"I`d never heard of country-fried steak before. It`s great! I love fried food."