Miley Cyrus' boyfriend struggles to watch her steamy scenes

Miley Cyrus' boyfriend finds it "hard" to see her kiss another guy.

The 16-year-old singer-and-actress, who locks lips with co-star Lucas Till in 'Hannah Montana: The Movie', admits her real-life partner Justin Gaston struggled to watch the steamy scenes.

Miley said: "He's seen the movie, and it's only acting, so I guess you have got to keep that in your mind. And I'm sure it's probably a little hard, but we're actors. We have got to be good at our jobs."

Lucas insists his relationship with Miley is purely platonic and he formed a friendship with Justin, 21, while they were shooting the teen movie.

He said: "Justin is a nice guy. I didn't see any animosity there for any reason."

Although underwear model Justin managed to contain his jealousy during Miley's kissing scenes - her former on screen love interest Cody Linley wasn't so understanding after learning Miley's character has moved on.

Cody joked: "She's got a boyfriend in the movie. Where is he? I'm going to lay the smackdown!

"Everyone knows her real boyfriend is right here. I can probably whoop Lucas' a*s. I'm just joking, but if you do want to fight, let's go!"