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!”

Miley Cyrus wants to have children within 10 years.

The 16-year-old star – who is dating underwear model Justin Gatson, 21 – can see herself being a glamorous “soccer mom” like former Spice Girl Victoria Beckham.

When quizzed on what she will be doing in a decade, Miley said: “I’ll be a soccer mom – like Posh Spice!”

“I’ll be there in my heels cheering on my kids, ‘Go, team, go!’ But I’ll have no idea what’s going on.”

However, the singer-and-actress has no plans to give up on her career when she does become a mother.

The “Hannah Montana” star added: “I’d love to be a director. I also want to keep going with my music. Maybe I can write music for movies.”

Miley – who recently claimed she is “best friends” with former boyfriend, 16-year-old Nick Jonas – also said she is “very happy” in her relationship with an older man.

She told KIIS-FM radio host Ryan Seacrest: “I’ve dealt with relationships with people my age. They can be harsh and judgmental.”

Miley has previously insisted the age difference between her and Justin “doesn’t worry” her.

She said: “We’re just really happy with the way everything has worked out.”

“He has been a really great friend, more than anything. It’s annoying that everyone started judging.”

“I’ve learned to go into our friendship with an open mind and not really worry about the age or anything.”

Miley Cyrus ”loves spending time with” Justin Gaston.

The 16-year-old “Hannah Montana” star hopes the 20-year-old underwear model will join her during the festive period because they have grown so close.

She said: “I love to spend the holidays with my friends. I think that Justin and I are really good friends, and we love hanging out and spending time together.”

However, Justin said he had “no idea” if he would be joining her.

“He added: “I don’t know where she’ll be, but I hope she has a good time. I’ll probably be around somewhere and hanging with the family.”

It was recently claimed that Justin – who has landed a modeling deal with Roberto Cavalli since he started dating Miley – is only using the young star to boost his celebrity status.

A source said: “You start to think he’s in this for fame. She needed someone, and her father Billy Ray thought this was perfect for her image.”